RrR,01l111 Stud,u Vol 15 No G pp 507-520 1981Pnnu:d In Grc:H Brlt;l.m

IS'b I0034-3404/81/060507-1410200/0

Perg:llffion PeelS Lld«:> 1981 Regional Studies ASSOClatlon

'\

Transport Changes Generated byDecentralized Offices: A Second Survey

P W DANIELSDepartment oj Geography, Umverslty oj LIverpool, Roxby But/dlng, PO Box 147,

LIVerpool L69 3BX, U K

(ReceIved August 1979, In revISed form AprIl 1980)

DANIElS P W (1981) Transport changes generated by decemrallzed officesa second survey, Reg StudIes 15, 507-520 An earlIer nudy of theJourney towork to decentrahzed offices was replIcated at the same estabhshmems In

1976 Despite dIfficulties In comparmg [WO secs ofessentially cross-sectIonaldata, the results suggest that repl..cement staff and new recruits SInce 1969have not changed to any sIgmflcant degree the structure of mode chOIce forthcJourney CO work antIcIpated from the earlier findmgs Pnvate transportcontinues to dommate the travel mode changes generated by decentrahzedoffices and although aggregate level use ofpublic transport has contmued tofall there have been margmal Improvements In the level of utlhzOltJonpartlcularly m the GLA

Journey to workTravel mode

Decentralized officesBntam

DANIELS P W (1981) Developpements dans le domame du transport a lasUite d'une decentrahsatlon des bureaux une deuxJeme enquete, RtgStudlts 15, 507-520 Une etude anteneure sur le traJet au travail dans desbureaux decentrahses a ete refane, comport.mt les memes etabhsscmentsmalS pour I'annee 1976 En deplt des dlffacuhes provenant d'unecomparalson des donnees essentleUement par tranche, Ies resultats lalssentsupposer que depuls 1969 le nouveau personnel, SOlt rempla'tant, SOlt recrue,n'a pas modlfie a aucun degre non-negligeable la structure prevue du chOlxde moyen de transport pour le traJet au travad Le transport pnve continue adommer les modIfications dans Jes Ch01X de moyen de transport qUiresultent de la decentrahsOltlon des bureaux QUOlque le nJveau globald'usage des trampons en commun alt contmue de dlmmuer, 11 y a eu desprogres margmaux pour ce qUI est du nJveau d'un!IsatlOn, sunout dans laGLA

TraJet au travaIlMoyen de transport

Bureaux decentralisesGrande-Bretagne

DANIEl ... P W (1981) Wandlungen lID Transponwesen aIs FoIge derDezentrallSlerung der Verwaltungebaudc em zwclter Bcncht, Rtg StudIes15. 507-520 Eme fruhere Swdle des Arbcltsweges zu dezentrabsIenenVerwaltungsstdlen wurde an densdben Instltutcn Im Jahre 1976wlcderholt Trotz Schwlerkeltcn belm Verglelch zwcler, lID wescnthchenden Durchschmtt beschrcJbendcn Relhcn von Angaben, deutet dasErgebms dClCauf hm, dass weder Ersatzpersonal noch neue Angcstelltc selt1969 dIe Struktur der gewahltcn Art der Anrclsc Zur Arbelt, die man OIU(

Grund der fruheren ErgebOlsse erwartet hattc, wcsenthch geandert habenPnvattransport beherrscht weltcrhm die Wahl der AnrelSeart, die dieDczcntrallslerung deT Verwaltuhgsgebaude mlt Slch gebrachr hat Obschondie Benutzung offenrhchcr Transportmlttcl uberhaupr welter gefallcn 1st,gab es Verbcsserungen an dCT unteren Grcnzc dcr Ebene der Benutzung,besondcrs lffi Geblet der Vcrwaltung von Gross-London

1'15 " IS G

AnrelSC Zur ArbcltArt der Anrelse

Dezentralulcrung der VerwaltungsgebaudcGrossbntannlcJ1

507

UK Data Archive Study Number 1837Follow-Up Survey of Journey to Work and Residential Location Patterns of Office Workers in Decentralised Offices, 1976

508 P. W. Daniels

INTRODUCTION

IN AN earlier paper in this journal (DANIELS,1972) some of the changes in travel modechoice for the journey to work whichfollowed the relocation of office establish­ments from central London to destinationsthroughout Britain were reported. Theprincipal conclusion from that study wasthat, irrespective of where an office workerhad previously been employed or hisoccupation status, it was more than likelythat private transport would be used for thejourney to work to the decentralizedlocation. It was noted that there werelocational variations in the dominance ofprivate transport; these were related to theproportion of the staffin decenrralized officeswho had previously travelled to work incentral London, the proportion of car­owning households and the ratio ofclerical tonon-clerical workers. There was also a cleardistinction between the journey-to-workeffects of relocating offices to places withinGreater London and the South East and lessclearly defined changes at offices which hadmoved to a set of provincial zones. 1

There is scope for uncertainty about themedium- or long-term validity of theconclusions of the earlier study undertaken in1969. Within 2 or 3 yr of its originalrelocation an office will experience staffturnover or expansion which will result inthe recruitment of new staff who may havedifferent travel habits. The relative merits ofcompeting modes for the journey to workperceived by continuing employees may alsolead to some modifIcation of the travelbehaviour originally recorded. Such con­siderations motivated a return to the officeestablishments which had co-operated in theearlier study in an attempt to collectinformation which would permit compar­ison with the previous results. There havebeen a number of cross-sectional studieswhich have directly or partially examined thejourney to work at decentralized offices(W ABE, 1967; HAMMOND, 1968; BATEMAN etaI., 1971; D ANIELS, 1972, 1973) but there havebeen no attempts to monitor the results. ThisIS almost certainly a product of themethodological problems which arise andsome of the considerations which had to beaccommodated by the present study havebeen outlined elsewhere (DANIELS, 1979).

To effect a proper comparison betweentwo sets of data generated several yearsapart it is necessary to isolate those changeswhich are caused by wider trends, such

as mcreasmg car ownership or decliningpublic-transport utilization, from thosewhich are the product of particular changesin the attributes of the survey population.The latter are best examined by tracing thejourney-ta-work adjustments by office staffpresent at and between the times of bothsurveys and those of employees recruitedafter the initial survey. The importance ofthis approach was recognized and an attemptmade to identify offtce staff in these twogroups to see, for example, whether travelmode choice by more recent recruits wassignificantly different from that of staffalready present at the time of the fIrst study.In practice, it proved difficult to construct ananalysis around this distinction.

Just over 27% of the office employees whoparticipated in the second survey in 1976were employed at the survey locationsduring the previous study; 72% actuallyrecalled completing the questionnaire butonly 37% of them were sure tha t they haddone so. The remainder could only recall thatthey "may have" completed that question­naire. The levels ofrecall also varied from oneoffice to another and it was reluctantlydecided not to pursue this line of analysis butto concentrate on a comparison of the overallset of respondents. It must be clearly statedtherefore that what follows is a comparisonof two cross-sectional studies in which theadjustments in the travel-ta-work behaviourof decentralized offtce staff can only bepartially explored. An analysis based on acomparison of more recent and longer-termrecruits has however been reportedelsewhere for a limited number of individualoffices (D ANIELS, 1978).'

While these limitations are clearly signifi­cant, it is believed that a useful purpose isserved by a comparison between theaggregated results of the two surveys.Excluding the long-term trends in travelbehaviour incorpora ted in the results of thesecond survey, it seems useful to establishwhether the shifts in travel mode choiceidentified in the fIrst survey have continuedto erode the position of public transport.Occupation status and previous workplacewere important predictors of change in theearlier study and there is now an opportunityto see whether they continue to be importantas the composition of the decentralized officelabour force has changed. After an outline ofthe survey procedure, the remainder of thispaper broadly follows the structure of itspredecessor with an overall analysis of theextent of travel mode transfer and its

Transporl Changes from Office DecenlraiIzallo/1 509

relationshIp wIth prevlOu's workplace andoccupatIOn status of office staff Themfluence of employee resIdential dIstrI­butIOns, as defined by trIp length for theJourney to work, on the ratio of publIc- toprIvate-transport trIpS m each zone wIll thenbe cornpared for the two surveys

THE FOLLOW-UP SURVEY

A total of42 offIces agreed to partIcIpate mthe follow-up exercIse our ofan orIgmal rotalof 63 (Table 1) Over 23% are offices Inpubhc admInIstratIOn and defence wIthmsurance, bankmg and finance, and profes­SIOnal and sCIentific servIces beIng the twolargest groups representmg the commerCIalsector Even though the sample IS smaller thedIstrIbutIOn of respondents from eachmdustrIal sector IS broadly SImIlar to that forthe first survey wlth almost half (21) of thepartIcIpants beIng head offices and 14% (6)regIOnal offices The remamder are el ther soleoffices or sectIons wlth head/regIonal head­quarters stIll located m central London A fewfirms dId not any longer consIder themselvesas "decentralIzed" and referred ro a questIOnabout whether they had partIally or com­pletely moved from central London as "notapplIcable" On the baSIS of those firms thatdId respond, complete moves are margmallyoverrepresented m the second survey COm­pared wlth ltS predecessor or the dIstrIbutIOnof partial and complete moves recorded bythe LOCATION OF OFFICES BUREAU (1976)

The firms whIch dId not agree topartIcIpate agam dId not gIve precIse reasonsapart from "pressure at work" and It IStherefore dIfficult to estImate the bIas m thesecond survey Almost all the non-

partICIpants are located wlthm the South EastRegIOn, the two refusals m the prOVInCIalzones were from firms no longer opera tlngfrom theIr earlIer addresses Th,s also applIedto some of the offices In the South East andtwo firms whICh OrIgInally agreed to co­operate subsequently wlthdrew

The employee response rates (without afollow-up procedure) to a questIOnnaIredIstrIbuted at theIr place of work show adeclIne from the level achIeved In 1969 (TableI) In the second survey 47% of thequeStIOnnaIres were returned In a condItIonsuitable for processmg as compared to 61 1%preVIOusly However, If only those officeswhICh partiCIpated m both surveys areconsIdered the proportIOn falls to 54 1%ThIS IS still substantially better than the figurefor the second survey even though anIdentical survey procedure WIth a slIghtlymodIfied questIOnnaIre was used The declInem employee response rates may be symp­tomatic of an IncreasIng reluctance andmdlfference on the part of organIZatIOns andthe pubhc to prOVIde mformatlOn on avoluntary baSIS about aspects of theIr dallylIves Some office staffmay also have found ItdIfficult to understand how they could assIstm a survey of decentrahzed office workerswhen they may have been recruIted severalyears after the OrIgInal move by theIremployers The AmerIcan StatIstIcalASSOCIatIOn has recently expressed concernabout problems of thIs kmd and has proposedmore rIgorous pretestmg and vettIng ofsurveys before they are undertaken (SOCIALSCIENCE RESEARCH COUNCIL, 1979)

It IS also worth stressmg at thIS pomt thatthe aggregated analySIS reported here hasbeen constramed by the deSIgn of theprevIous survey The orgamza tlOn of the data

• Tab/~ 1 Total offices and respondents in surlJ~Y zones, 1969 and 1976

No of respondent 0/0 of tnpsZone offices Toea] respondents In zone

1969 1976 1969 1976 1969 1976

GLA 20(33)* 14 1788(2983)t 1077(2943)t 599 366OMA 16(23) 8 1253(2327) 915(1778) 538 515OSE 13(15) 9 980(1594) 959(1637) 61 4 586

PrOVinCIal } 5(10) 4 462(796) 358(911) 580 3923(11) 2 313(859) 390(1278) 364 305

zones 6(13) 5 2347(3226) 4061(7955) 727 510

Total 63(105) 42 7143(11,785) 7760(11,502) 61 1 470

*Total offices orIgmally appro:ached for 1969 survey m parenthesestTotal employees recelvmg questIonnaires In parenthesesSour", Office-dISpersal Journey-ro-work survey (1969) and follow-up survey (1976)

510 P. W. Danie/s

for individual offices into zones, especiallyoutside the GLA and OMA is not entirelysatisfactory; the quality of the conclusionsmay have been enhanced by classifying theoffices on the basis of the kind of locationoccupied (major or intermediate provincialcity for example). The sample may beinsufficiently differentiated in a way whichwould have aided interpretation of some ofthe anomalies or apparent stability shown bythe data for the two time periods. Suchdifferentiation would also have formed theframework for devising indices whichsummarize, for example, the kind and qualityof public-transport services in the areas towhich offices have moved. This wouldimprove the possibilities for distinguishingbetween constraint as an explanation formodal choice changes and preference for onemode of travel rather than another in asituation of alternatives.

MODE CHOICE ATDECENTRALIZED OFFICES: 1969

AND 1976

It may be useful to begin wi th a briefcomparison of the modal choice distributionsfor each zone for the two survey periods. In1969 some 60% of the work trips generatedby decentralized offices could be classified asprivate transport (car drivers, car passengers,trips on foot); in 1976 the equivalent figurehad risen to 66% (Fig. 1)' Public transportwas already being used at relatively low levelsin the first survey and this has clearlycontinued. Disaggregation shows, however,that this trend masks some stability in thelevel of bus trips for the journey to work atapproximately 26% of all journeys whiledaily journeys by train and other (mixed)combinations have suffered most of thedecline in patronage of public transport.Within individual zones at each office site theavailability of public transport places COn­straints on use so that in the OMA and OSEthe share of public transport has decreasedmore consistently than in the provincialzones. Here, a number of the offices in thesample are located in metropolitan areaswhere public transport is more accessible forjourney-to-work travel. Indeed it is verylikely that the decline in the share of all tripsby public transport is directly related to thetype and size of urban area to which officeshave relocated (DANIELS, 1980). The prob­lems created for users of private transportfor work travel in the larger urban areas,

especially where travel to the centre isinvolved, may be sufficient to encouragetravel by public transport, particularly buses,although at levels which are still lower thanthose prevailing prior to decentralization.

It is also likely that the increased share ofprivate-transport journeys in the secondsurvey is a product of the secular trend in carownership. For many households this re­moves the need to consider public transportas an alternative for the journey to work(Table 2). Access to a private or company Cardoes not immediately mean that modalchoice will be dominated by this factor but itseems certain that any changes in carownership between the two survey swillaffect the structure of mode choice. In everyzone the proportion of households without acar has declined; 27.6% of the respondents inthe first survey did not travel to work fromcar-owning households but this had de­creased to 20.3% in 1976. It is worth notingthat the 1971 Census showed that 48.2% ofall households in England and Wales did nothave access to a car so that office workerhouseholds are also clearly more likely topossess a private car than all households(OFFICE OF POPULATiON CENSUSES ANDSURVEYS, 1973). Although it is only possibleto make an approximate comparison be­tween the levels of car ownership in theeconomic planning regions and the zonesused in this study, this differential appears topersist at the regional level; in one of theprovincial zones which roughly coincideswith the North West and HumbersideRegions (zone 5), 28.7% of the respondentsdid not possess a car in 1969 whereas theequivalent figure in the 1971 Census wasapproximately 55%. By 1976 the figure foroffice workers had decreased to 15% and thisvery likely represents a larger discrepancyfrom the overall regional figure than in thefirst survey.

The contribution of car ownership tomodal choice is given added weight in thisinstance by the substantial increases in theproportion of office staff from householdswith two or more cars. The increases arefairly constant across all the zones and whilemany of the population at large are acquiringtheir own vehicles for the first time, officeworker households already having an above­average level of car ownership in 1969 havegone on to acquire a second vehicle. Thedifference between the first and secondsurveys may, as will be seen later, be relatedto contrasts in the occupational structure ofthe two samples. Whatever the precise

Transport Changes from Office Decentra/'zatlOn 511

50 <D , ,

.,

"

®

30,.I!

20- r

!~t~~~~~ ~

11969 01976

FIg 1 Tralltl mode chOice at decentrab:ud offices, 1969 and 1976

'0-

Tablt 2 Household car ownershIp DJ employees at deuntrahzed offices, 1969 and 1976*

, Household car ownershIp

Zone YC41lrNo c:n One c.ar Two+ cars Total

GLA 1969 447(255) 987(564) 317(181) 1751(100)1976 136(148) 520(567) 260(284) 916(100)

OMA 1969 250(204) 755(61 7) 218(17 8) 1223(100)1976 103(122) 534(630) 210(248) 847(100)

OSE 1969 217(223) 614(630) 143(147) 974(100)1976 100(11 3) 574(648) 212(239) 886(100)

ProvIncIal 1969 658(374) 935(53 6) 153(88) 1746(100)zones 1976 804(270) 1818(610) 357(120) 2979(100)

Tocal 1969 1572(276) 3291(578) 831(146) 5694(100)1976 1143(20 3) 3446(612) 1039(185) 5628(100)

*Percentages m pOl.renthesesSources Office-dISpersal Journey-co-work survey (1969) .:Inci (cHow-up survey (1976)

512 P. W. Daniels

explanation thete is cleat evidence that theoffice workers in the second survey havegreater potential mobility and flexibility ofmode choice for their journey to work thanmost other groups of workers and this isincorporated in the enhanced share of privatetransport illustrated in Fig. 1.

EFFECT OF CHANGES IN THELABOUR FORCE

The structure of travel mode utilizationshown in Fig. 1 is to some degree the productof changes in the method of travel for thejourney to work by offtce workers formerlytravelling to other destinations, especiallycentral London. It was clearly shown in thefirst survey that the largest proportionalcontribution to the overall increase injourneys to work by car drivers at decen­tralized locations could be traced to respon­dents formerly travelling to central London.In common with most commuters to thisarea the majority used public transport(60-70%) and, whether through choice orabsence of alternatives, subsequently becameusers of private transport. By 1976 thepotential contribution of these employees toreinforcing the role of private transport hadbeen eroded; they comprised 33.5% of thesample in the flrst survey, declining to 14.4%in the second (Table 3). The smallest decreasehas occurred in the GLA but the general trendis consistent. Local recruits,' including officeworkers entering employment for the flrsttime, have come to dominate the labour forceIn decentralized offices (Table 3) with a

notable increase in the share of the latter. Theresult is that the shift to private transport hasnot been as large as it would have been if theprevious workplace structure of the 1969respondents had been replicated in 1976.

Although post-decentralization modechoice for the journey to work by formercentral London employees follows theexpected pattern its significance has clearlydiminished in the OSE and the provincialzones. This situation has been neutralized tosome extent by a higher initial dependence onpublic-transport modes for trips to centralLondon amongst the 1976 sample followedby a higher propensity to switch to privatetransport than before. This larger relativeshift to private transport is characteristic ofcentral London workers in all the zonesexcept in the GLA. Here the proportion ofwork trips by bus (20%) represents amarginal improvement over 1969, the onlyarea where this has occurred. Even allowingfor sampling error, there is therefore someevidence that in circumstances where thenetwork coverage ofpublic transport and thelocation of office development coincide,central London workers will continue to usethis method of travel.

Staff recruited from other towns orsuburbs are the second group most likely tocontemplate changes in travel mode for thejourney to work. This group has maintainedits overall position (Table 3) while theproportion of private-transport journeys isgenerally higher in the second survey withmost of the transfers at the expense of publictransport. The proportion engaging in cardriver or car passenger trips is consistently

Table 3. Decentralized office employees: previous location of workplaces. 1969 and 1976*

Previous place of employment

NotZone Year Central Same town Another town previously

London or suburb or suburb employed Total

GLA 1969 837(47.4) 294(16.7) 483(27.4) 151 (8.6) 1765(100)1976 322(32.6) 198(20,0) 322(32.6) 147(14.8) 989(100)

OMA 1969 536(43.2) 257(20.7) 322(25.9) 127(10.2) 1242(100)1976 213(24.0) 235(26.5) 233(26.3) 206(23.2) 887(100)

OSE 1969 202(20.8) 314(32.3) 294(30.3) 161(16.6) 971(100)1976 101(11.0) 246(26.8) 290(31.6) 278(30.3) 917(100)

Provincial 1969 349(19.7) 601(33.9) 463(26.1) 358(20.2) 1771(100)zones 1976 244 (74) 1006(30.5) 805(24.4) 1244(37.7) 3297(100)

Total 1969 1924(33.5) 1466(25.5) 1562(27.2) 797(13.9) 5749(100)1976 880(14.4) 1685(27.7) 1650(21.0) 1875(30.8) 6090(100)

*Percentages in parentheses.Sou"es: Of6ce-dispersal journey-to-wotk sutvey (1969) and follow-up sutvey (1976).

Transport Changes from Office Decentra1J:<:atJOn 513

hIgher rhan for rhelr prevIOUS work trIpS, apattern noted m the first survey andaccentuated m 1976 by a decrease In the levelofJourneys to work made on foot

Local recrUIts are least lIkely to need tomake changes m the method of travel for theJourney to work ThIs group's share of thetotal labour force (excludmg the prevlOuslyunemployed) has also remaIned relatIvelyconstant Smce there IS a hIgher mmaldependence on publIc transport lt 15 lIkelythat any modal shIfts whICh do occur WIllfavour prIvate transport ThIS has mdeedoccurred bu t whIle the proportlOn of workJourneys by publIc transp?rt IS lower than Inthe first survey It continues to be used at amuch hIgher level than that exhIbited by theother two groups Much of the shIft m thesecond survey has been from bus to carpassenger trIpS, especIally In the provmClalzones, but pubhc transport stIll accOunts forwell over 40% of all Journeys

In vIew of the substantIal mcrease m thenumber of local recrUIts claSSIfied as notprevlOusly employed lt IS apparent that themode chOIce decISIOns by these employeesnow play a crItlcal pare In determmmg thestructure of Journey-co-work travel todecentrahzed offices These effectIvely re­present "new" or addmonal trIpS In the localtransport system In 1969 they revealed aclear OrIenratlOn towards pubhc transport,partIcularly m the metr?pohtan region and mthe provmClal zones The much larger groupof these employees In the second survey now

rely more on prIvate transport than before,car drIver trIpS have mcreased from less than20 to 30-35% m the South East and m theprovIncIal zones the prInCIpal change hasbeen m car passenger trIpS from ap­proxImately 20% In 1969 to 30% In thesecond survey The offices In the GLA are theonly places where first-tlme employees usepublIc transport, prInCIpally buses, at aroundthe same level (30%) as m 1969

The relatlOnShlp between the prevIousworkplace varIable and the characterIstIcs ofthe Journey to work at decentralIzedlocatIOns IS remforced If the occupatIOn statusof employees IS also Included To a degreethese are surrogates since the majorIty oflocalrecrUIts are In clerIcal occupatIOns and non­local recruits are more hkely to be InmanagerIal and profeSSIOnal posmons It IStherefore Important to note that although theshare ofcentral London recruits has decreasedbetween the two surveys, the proportlon ofmanagerIal respondenrs IS hIgher m thesecond survey (Table 4) It was shown In thefirst survey that these were mamly respon­SIble for enhancmg the role of prIvatetransport although the Impact of theIrdeCISIons was not as large as that for clerIcalstaff The most Important dIfference between1969 and 1976 IS the shIft of emphaSIS awayfrom car drIver trIpS by managers Bur thIShas not reduced the overall dommance ofprIvate modes because of an mcrease m thenumber of managers travellIng to work as carpassengers, perhaps a reflectlon of the growth

Table 4 Dtuntraltzed oJfiu tmpJoyees OlCupatwn charaetenstlCs, 1969 and 1976

OccupatIOn group

Supervlsory/«chnIc>l/aSSIstant

Zone Year Man.agenOlI ProfeSSIOnal professlon.al Clencal Total

GLA 1969 149 (85) 248(14 1) 415(23 6) 915(520) 1761(100)1976 205(205) 134(134) 166(166) 472(471) 1002(100)

OMA 1969 97 (78) 117(94) 201(162) 788(63 4) 1242(100)1976 137(15 1) 21 (23) 184(203) 530(586) 905(100)

OSE 1969 36 (3 7) 23 (2 4) 138(142) 730(749) 975(100)1976 130(13 8) 23 (23) 190(20 1) 550(582) 945(100)

ProvInCI..l 1969 48 (27) 52 (30) 218(12 4) 1410(803) 1756(100)zones 1976 195 (5 7) 17 (05) 604(176) 2566(749) 3428(100)

Total 1969 330 (5 8) 440 (77) 972(170) 3843(670) 5734(100)t1976 667(10 6) 195 (3 1) 1144(182) 4118(656) 6378(100)

*Percentages In parenthesestTotals Include a small number of"orher" employees, 149 (1969) and 154 (1976), notllSted separately

In the table I

Soum, Office-dlSper",IJourney-to-work survey (1969) and follow-up survey (1976)

514 P. W. Daniels

of car sharing during the 1970s. The majorityof managers are reluctant to walk to theirofflces even if they reside close enough to doso and in all the zones there has been a markeddecrease in the proportion travelling in thisway. There has also been a marked decline inthe share ofbus and train journeys outside theGLA and OMA but in these two areas themajority of managers reside further fromtheir offices than most other office staffand insome cases the train clearly represents a viablealternative to the private car for access to afew of the suburban offices in the GLA inparticular. It is clearly difficult to say whetherthis really only represents a minor butpossibly important back to public transportat some locations.

The concept of a threshold in the share ofprivate transport trips is supported by thetravel behaviour of employees In

supervisory jtechnicaljassistant professionaloccupations. Not only is the proportion ofcar journeys lower in 1976 but in almost allareas bus journeys account for more tripsthan was the case before decentralization.The GLA is again the best example; theproportion of journeys by car drivers tosuburban offices is lower than it was prior torelocation while the share of car passenger,walking, and bus trips has increased. In theOMA car journeys have increased in linewith expectations but to a lower overall levelthan was reached in the earlier survey.

Since local recruits and clerical workers arebroadly synonymous it is not surprising tofmd that only some 20-30% of the latterdrove to work in the second survey. As in thefirst survey, this represents a marginaldifference over the modal structure of tripsmade to other workplaces. The clearestfeature relating to this group to emerge fromthe second survey is their increased depend­ence on vehicle sharing for the journey towork; indeed in the provincial ZOnes thisaccounts for the majority of private­transport journeys and builds upon •characteristic already evident in 1969. Thismeans that clerical workers have continuedto move over from public transport and,given the size of the sample, more reliabilitycan be placed on this trend than for someother observations in this study. Only in theprovincial zones is there any evidence ofstability, elsewhere, and particularly in theOMA and OSE where public transport doesnot often represent a viable alternative, theshare of bus journeys has declined sharply. Inthe GLA bus journeys by clerical workers inthe second survey are more numerous than

for their previous trips but the net result isstill a lower level of utilization than wasevident in 1969.

THE SCALE OF TRANSPORTCHANGES

Using the evidence from the samplesurvey, an atrempt was made in the firstsurvey to estimate the overall level ofchangesin public-jprivate-transport utilization forthe journey to work. The procedure has beenrepeated for the data from the second surveyand the results can be compared in Table 5.The statistics in the table are based on theassumption that car driver and bus trips arethe chief competing modes at decentralizedlocations and can therefore be used as indicesof the overall changes in mode choice afterrelocation. An attempt is made to estimatethe actual increase or decrease in these tripsby using the total trips by each of them inevery zone (all six) for both present andprevious work journeys and then expandingthese values to provide the estimate ofoverallchange. To do this it is important todistinguish between trips which were alreadyundertaken in the local networks to whichthe offices have moved and new tripsintroduced into these networks as a result ofthe appearance of the new establishments.Therefore all trips made to the same town orsuburb (i.e. local employees) have beendeducted from the total number of presenttrips (see Table 5 for key to calculations). It isnecessary to assume that previous trips to thesame town or suburb were made todestinations in the vicinity of the decen­tralized office; this is clearly not always thecase because the office may be located on theperiphery of an urban area some way fromthe principal business concentration but thereis no alternative data available to rectify thisproblem. The number of previous journeysby each mode undertaken outside localnetworks has also been calculated for eachzone in order to estimate the absolute andpercentage change in the use of the modalindices. The expansion fractions used inTable 5 are derived from a comparison of thenumber ofrespondents at each office with thetotal staff complement. Values of theexpansion fraction range from 1.93 in theOMA to 3.20 in zone 5 (provincial zone). Thefractions for the second survey are unfortu­nately rather higher because of the lowerresponse rate. The resulting estimates are

Transport Changes from Office DecentralizatIOn 515

Table 5 ESllmated changes III the number of (A) car dnver, and (8) bus tripS 10 offius /11 surlley zone.l, 1969 alld 1976

PrevIouswtal tripS

EstImated externalAdditIonal tnps to EApansIOn [Otal to local

Zone 10cOIl networks* fractlOn additIOns networks 0/0 change

1969 1976 1969 1976 1969 1976 1969 1976 1969 1976

(A) Car drivers

GLC 548(306):1: 347(337) 1 66 288 909 999 505 593 +800 +685OMA 420(334) 303(33 1) 1 85 1 93 777 585 344 235 + 125 9 + 148 9OSE 272(278) 296(30 I) 1 62 1 96 441 580 204 227 + 116 2 + 1555

fI3(244) 103(288) 172 214 194 220 53 60 +2660 +2667Provlnm! 68(21 4) 119(305) 274 320 186 381 99 163 +879 +1338

zones 161(153) 376(23 2) 185 1 95 298 733 148 312 + 1013 + 134 9Total 1582§ - 1544 - 2805 2488 1353 1590 +1073 +565

(B) Bus

GLC 138 (7 7) 109(106) 166 288 229 314 256 236 -103 +331OMA lIS (9 I) 39 (43) 185 193 213 75 196 100 +87 -250OSE 19 (1 9) 36 (20) I 62 196 31 71 134 155 -769 -542

} 60(129) 24 (67) 172 214 103 51 93 51 +108 00Provlnm] 14 (44) 12 (3 I) 274 320 38 38 107 112 -644 -661

zones 109(176) 311(192) I 85 195 202 606 302 413 -331 +467Total 455 - 531 - 816 1155 1088 1067 -250 +83

*AddItIonal tripS to local networks = cot.l present tnps on local network - (present tripS by local recrUIts bymode X - preVIOUS trIpS by local recrUIts by mode X)

tPrevlOus trIpS externa] to local networks = [Otal preVIOUS tnps by mode X-prevIOUS tnps by local recruns bymode X

tValues In parentheses are addItIOnal tnps [0 local networks expressed as;l percentage of all present tflpS In eachzone

§These figures exclude Journeys now undertaken by employees claSSIfied as "not previously employed"Source Office-dISpersal Journey-ta-work survey (1969) and follow-up survey (1976)

very likely less accurate because of thISconsldera tIOn

The most Important statIStlcs In Table 5are those whIch relate to percentage changeIn the number of trIpS USIng each mode Inthe first survey (on the baSIS of data from all63 offices) the total addItIonal car drIverJourneys In local networks represented agrowth of 1073% over the number ofJourneys by car drIvers to other workplaceloca tIOns Although the 1976 results onlyrelate to 42 establIshments (therefore theabsolute figures are lower) the percentagechange IS almost half tha t of the first survey at565% ThIS lower transfer rate undoubtedlyreflects the Increaed promInence of localrecruIts In the office labour force, IncludIngemployees not prevIOusly employed It ISstrIkIng, however, that WIthIn IndIVIdualzones some of the percentage Increases arehIgher than In 1969, 1555% In the OSEcompared to 1162% prevIOusly, 1349% InprovIncIal zone 6 compared to 101 3% In1969 It IS also apparent that the addItIonal

trIpS to local networks by car drIversexpressed asa percen tage ofall present trlps Ineach zone IS generally hIgher for the secondsurvey Therefore the slower growth raterecorded In 1976 does not necessarIly mean adeclInIng rate of transfer to prIvate-transportmodes SInce It has been shown that more localrecruIts and others are now USIng these modesthan was the case In 1969

GIven the changes In the structure of thelabour force by prevIOUS workplace It IS

perhaps not surprISIng that the changes In thenumber of bus trIpS for the Journey to workwhIch were negatIve In 1969 (- 25%) havebeen reversed to an Increase ofJust over 8%(Table 5) Although In the OSE andprovIncIal zone 5 the negatIve change hascontInued, there IS a marked reversal InproVInCIal zone 6 from -313 to +46 7%On rhe other hand part of thIS major reversaldoes not reflect the use of pubhc bus serVICesbut the extensIve use of prIvate hIre buses byemployees In a large office whICh has movedto Glasgow The SIgnIficance of the Improve-

516 P. W. Daniels

ment in bus ridership should not, therefore,be overestimated for if it is expressed as apercentage of all present journeys in eachzone it is much less significant than car driverjourneys. This is the case despite the fact thatin Greater London and provincial zone 6 busjourneys comprise a larger proportion of alljourneys to work than in the first survey.

RESIDENTIAL LOCATION ANDMODE OF TRAVEL

It has been shown previously that there is agood relationship between residential lo­cation, using distance travelled as a proxyvariable, and the method of travel used forthe journey to work (DANIELS, 1972). Thishas again been examined wi th the da ta fromthe second survey using the percentage oftrips by car drivers and by bus at eachindividual office location as surrogates forprivate transport and relating the figuresobtained to the mean trip distances forjourneys to work at each location. Scatterdiagrams have been prepared for each of thezones in the South East and for the provincialzones using the same 42 offices for both years.

The 1969 data showed that the proportionof trips by car drivers increased as mean tripdistances increased and the values of, for theGLA, OMA and OSE were all significant atthe 0.05 level. In the OSE the value of ,indicated that 64% of the variation in cardriver trips could be explained by residentialdistribution (trip distance). The level ofexplanation in the GLA was lower thanelsewhere due to the better competitiveposition of public transport, especially forsome long-distance journeys to work by rail.In the provincial zones, however, therelationship was negative although, was notsignificant at the 0.05 level and leading to thesuggestion that the evidence was incon­clusive. The equivalent statistics for bus usersproduced a reciprocal negative relationshipwith mean trip length in the South Eastalthough it was only just significant for theoffices in the OMA where only 26% of thevariation in bus travel could be explained bythe distance between residences and work­places. Public transport was very importantat offices with high average trip distances inthe provincial zones but again the value of,was not significant. It was concluded thatdistance travelled was not an importantinfluence on modal choice outside themetropolitan area and factors such assettlement size, availability of competing

modes, and labour market characteristicswere probably more significant.

In order to permit a direct comparisonwith the data from the second survey, thevalues of , for 1969 have been recalculatedusing the smaller number of offices. Thosevalues which are significant at the 0.05 levelare indicated by an asterisk. Because there arefewer items it is of course more difficult todemonstrate a significant relationship andthere are fewer significant ,-values for thefirst survey data than indicated by the earliersummary. The scattergrams for the secondsurvey results are more confused so that thefitting of Curves which assume a linearrelationship between the two variables maynot be entirely satisfactory but for the sake ofcontinuity this procedure has been retained.While the directions of the relationships forboth car drivers and bus users is much asestablished for 1969, the confidence whichcan be expressed about, has diminished.

Hence, in the provincial zones theproportion of car driver trips is stillnegatively related to residential distributionbut the ,-value has decreased from - 0.56 to-0.34 (Fig. 2). For the same area, the positivevalue for bus users has been transformed to anegative curve in 1976 but an examination ofthe scattergram (Fig. 3) does not suggest thatthe direction of the relationship is signifIcantand indeed the value of, is only -0.10. TheGLA trend line for the second survey is alsoderived from a much wider scatter of pointsand neither of the correlation coefficients arenow significant at the 0.05 level. There was amuch clearer distinction between the share oftrips at any given distance by car drivers andby bus users in 1969 but it now appears that asdecentralized offIces settle into the suburbanenvironment in London they eventually findit necessary to recruit staff from further awayin response to growing competition in thelabour market from other organizationswhich have since moved to the suburbs. Inview of the socio-economic characteristics ofthese recruits and their dependence on publictransport, the result is a much more confusedrelationships than hitherto when clerical andrelated staff were obtained primarily fromlocal sources with senior staff using privatetransport (or in some cases public transport)to travel in from further afield. The OSE isthe only zone where the correlation betweenresidential distribution and the proportion oftrips by bus is higher than before, althoughthe relationship is still not signifIcant.

It seems that residential distribution is nowa less dependable predictor of travel mode

Transport Changes from Office Decentral,zatIOn 517

y CD ®0.0r 06S" r-O 15 r~ 0 ~e ! r 06'2

0

/, , •" /',..---__~ XX, /,' ,

X

r-07S" CDr" 0 15 00-® ,

r--O!l6 r··034

, ,0 ;;: ,

~'~0

0 x0 Xl 20 0 10 >J 0 ,0 20 0 '0 20

Mtan triP Jtngth (km)

-1969 .1976

FIg 2 Mean triP lengthJor the Journey to work to deunrra1Jzed offices and the proportIon of t"pj by car drillerS

20 25

(--010

r .. -007

"

-,---;--',

20 0

r·O 39

r- -0 37

)

/' ", ,,•

r_ 019

r_ - 0 59

\~, ,

CD

r .. ·O 77"

r--046

o 0+-----'--,--'--,o 10 200 10 200 10

Mean tnp length ( km)

• \969 • 1976

FIg 3 Mean triP length for the Journey to work to decentralized offius and the proportIon of 1rlps by bus

..

choJCe by decentrahzed office em ployees, andperhaps by other workers. than the firstsurvey had indIcated The reasons are nodoubt complex but they are probably notunconnected ro the dImInIshing cost dIffer­entIal between pubhc and private rransportfollOWing the energy CrISIS of 1973 and thecomphcatlOns Introduced by the growth ofcar sharing Dependence on rhe combustIon

engine IS also being modIfied by WIder use ofbicycles and motorcycles for Journey-to­work travel and these changes are hkely todIstort tradItIOnal assumptIons about therelatIonshIp between Journey distance. costand the way In whIch these determine themethod of travel chosen Th[s [$ partIcularlyrelevant In the case of car sharing where thepartIes Involved can agree to share costs. an

518 P. W. Daniels

i:

,.---~..--­.

CDr-O·14- /

,,

r.0·18

... .

o

0'

oO·

y CD080

o r_058-

0200·40 000·20 0'40 0·60 0·0 0·20

Friction co-efficient

.1969 .1976

Fig. 4. Mean friction coefficients for the journey to work to decentralized offices and the proportion of trips by car drivers.

040020

r __O_60·

0·20 0-40 0-60 0-11) 0'0

(£(D&@r· -0-'9

~ : ...~

010 0')0 0·100 0-0

Friction co·efficient

040

~ .. "

'"

~•• . ... .

060 0·0 020

CD

020 0 t,Q 0·60 0·80 00

020 040

~...~o

010~: .. .o O'+--~~-_~·--=-·_~.:::;,~

00

oo

o

• 1969 • 1976

Fig. 5. Mean friction coefficients jor the journey to work to decentralized offices and the proportion of trips by bus.

activity which insurance companies haverecently come to accept provided thatpassenger contributions do not amount tomore than the cost (including an allowancefor depreciation and maintenance) of eachJourney.

There is another, and possibly superior,independent variable which can be used toaccount for contrasts in the proportion oftrips by bus and car drivers and this is ameasure of the ratio of trip time to tripdistance referred to as the friction coefficient.

It is expected that car drivers will have highervalues for the friction coeffIcient than bususers in that per unit of distance the averagebus journey will consume more time than anequivalent car journey. If this is the case itshould be reflected in the proportion of tripsby each of these modes (Figs 4 and 5). It doesseem that this variable is relevant and it wasused in the first survey to show a strong andsignificant relationship between the modalvariable and mean friction coefficients atindividual offices, especially in the GLA and

Transport Changes from Office Decentralization 519

.'

OMA As expected, the eqUIvalent relatIOn­shIp for bus users was negative, I e per unlt ofdIstance travelled bus users took more tImeon each tnp, a consIderation whIch dIs­courages thIs choICe of travel mode If a betteralternatIve, usually pnvate transport, ISavaIlable On the baSIS of the 1969 data It wassuggested that the fnctlon coeffiCIent couldbe used to predIct the expected d,stnbutlOnof tnps by pubhc or pnvate transport atdecentrahzed office loca tlOns

The results from the second survey lendsome support to thIS suggestIon but wlth alower level of confidence In the predICtivevalue of the data The pnnclpal exceptIOn tothIs generahzatlon IS the prOVinCIal zonewhere the fnctlOn coefficIent for both busand car dnvers In 1969 generated a very lowvalue of r (see FlgS 4 and 5) but for the secondsurvey there IS a slgmficant cortelatlon fortripS by car (r=O 68) and for pubhc transport(r= -081) The fnctlonal effect of dIstanceseems to be a more Important determmant ofmode chOIce m the provmClal areas,elsewhere, although the dIrectIOn of therelationshIps In 1976 confirm the earherresults, m the maJonty of cases the values of rare not slgmficant and a WIder scatter ofobservatIOns again occurs The r-value IS onlystatIstICally slgmficant for the proportIOn ofbus tnps m the GLA and thIs probablyreflects the mfluence ofcongestIon on bus tnptImes whICh IS clearly unacceptable to longer­dIstance commuters, whIle m the OMA therelS a shghtly better aSSOCIatIon for theproportIOn of tnps by car dnvers whIChclearly confirms the advantages of travelhng­to work by pnvate transport In a SItuatIOnwhere pubhc transport represents, at best, ahmlted alternatIve

CONCLUSIONS

There has been a marked mcrease In thedependence of the decentrahzed offices In thIsstudy on local labour markets wlth onlymanagerIal and professIOnal staff recrUItedfrom elsewhere The scope for shorter workJourneys resultmg from thls change mIghthave been expected to "retard" the trends mmodal choICe antiCIpated from the results ofthe first survey The fact that decentrahzedoffice workers are more hkely than thepopulatIOn as a whole to travel fromhouseholds that own at least one car has tosome extent dIluted the effect of attractinglabour from local sources A notable mcreaseIn the number of respondents from

households WIth more than one car In thesecond survey has reduced the constramts onmode choIce by those households

It IS therefore not surprIsing that aJourneyto work usmg prIvate transport to replace aprevIOUSJourney by pubhc transport remamsthe dommant theme m the transport changesgenerated by decentrahzed offices Theyaccounted for 66% of all tnps In 1976compared to 60% In the first survey Officeworkers who preVIOusly used buses or tramshave contmued to be the prmClpal source ofnew prIvate-transport Journeys, along wlthrecrults taking up employment for the firsttime The latter represent a slgmflcant changeof emphaSIS smce they were shown to chooseprImanly pubhc transport m 1969 ThIsfea ture has been further remforced by thetendency for an addltlOnal proportIon oflocal recrUIts to travel to work by carNevertheless, there has been an mcrease of83% m the number of busJourneys added tolocal networks but It has already been stressedthat the slgmficance of thIs should not beoverrated because, as a percentage of all theworkJourneys m the sample, busJourneys aremuch less slgmficant than car dnver JOur­neys Greater London IS the only area wherethe eVIdence pomts to a more stable role forpost-decentrahzatlOn trIpS uSing prImanlypubhc-transport modes Managenal as wellas c1encal workers have contnbuted to anmcreased share for tram and bus Journeys(mcludmg the underground system)Elsewhere In the country, however, c1encalworkers have contmued to abandon pubhctransport and the fact that more managersthan expected used pubhc transport ISrelatively ummportant because as a groupthey compnse such a small proportIon of thedecentrahzed office labour force m theseareas

The way m whICh the GLA has emerged asthe one area where the trends antICIpatedfrom the first survey have not matenahzed ISworthy of further comment The reversals mthe downward trend of pubhc-transportutlhzatlOn mdlcated m the second surveymay be small but they do suggest thatcontinued decentrahzatlOn of employment,particularly to some of the larger subcentres,IS addmg complexlty to suburban commut­mg whIch IS havmg detnmentaJ effects on thetnp time and related advantages ofusmg a carfor the Journey to work The mcreased costspassed on to car users as a result may becausmg them to re-evaluate pubhc transportBecause the network of servIces In the GLA ISsuperIor, although not necessanly adequate,

520 P. W. Daniels

to that elsewhere it does present a viablealternative for many office workers especiallywhere it is necessary to travel substantialdistances. It is for this reason that managersand other high-status office staff appear to bemost responsible for reversing the character­istics of travel mode choice revealed by the1969 respondents. This could be important inthe long term SInce the structure ofoccupations in the quaternary sector isundergoing change which is largely, but byno means exclusively, at the expense ofclerical workers and if a larger proportion ofthe office labour force is to be occupied inwell-paid, higher-status, jobs then the scopefor longer journeys to work is likely to beincreased. This could be beneficial for public­transport services in the medium to longterm. A further consideration is that all theindications are that tertiary occupations aregoing to continue to expand their share of thelabour force at the expense of blue-collaroccupations and therefore some conventionalideas about the journey to work andresidencejworkplace location may need to bereappraised.

Acknowledgements-This paper is derived frompart of a research programme funded by the

Deparcmen( of che Environmcnt between October1975 and March 1979. The Department of theEnvironment does not necessarily concur with theinterpretation ofehe data or the views expressed by theauthor. The figures and tables are reproduced with thepermission of HMSO. A. W. Duffett's assistance withthe collection and preparation of the data included inthis paper is gratefully acknowledged.

NOTES

1. The offices arc grouped into six zones on the basisof distance from central London: zone 1 (GLA)­25 km; zone 2 (OMA)-26-75 km; zone 3(OSE)-76-150 km; zone 4--151-250 km; zone5-251-375 km; zone 6-376 km. For thepurposes of this paper zones ~ are generallygrouped together and referred to as the"provincial zones",

2. Unfortunately it proved impossible to implementa plan to interview selected office workers toestablish detailed attributes of any changes intravel behaviour and residential location betweenthe two surveys.

3. For method of classifying journey-ro-work tripsby mode see DANIElS (1972).

4. Local recruits aTC defined as employees previouslyworking in the same town or suburb. Residentialdata indicates that the majority of"Dor previouslyemployed" recruits aTC also obtained from the(own or suburb to which a decentralized office hasmoved.

REFERENCES

BATEMAN M., BURTENSHAW D. and HALL R. (1971) Office staff on the move, Research Paper No. 6, Location ofOffices Bureau.

DANIElS P. W. (1972) Transport changes generated by decentralized offices, Reg. Studies 6, 273-289.DANIELS P. W. (1973) Some changes in the journey to work of decentralized office workers, Tn Plann. Rev. 44,

167-188.DANIELS P. W. (1978) A Follow-up Study oftheJourney to Work at Decentralized 0ffices;n Britain (Part II): Case Studies

at New MaIden, Southampton, Leicester and Durham. Departments of the Environment and Transport, London.DANIELS P. W. (1979) Office dispersal and the journey to work in Greater London, in DANIELS P. W. (Ed.) Spacial

Patterns oJ Office Growth and Location, pp. 373-400. John W,ley, London.DANIELS P. W. (1980) Office Location and theJourncy to Work: A Comparati!)c Study o.-fFive Urban Areas. Gower Press

and Retail Planning Associates, Farnborough.DEPARTMENT OF THE ENVIRONMENT (1974) Strategic Plan for the North West. HMSO, London.HAMMOND E. (1968) London to Durham: A Study ofthe Tran~rcr oJrhe Post Office Savings Certificatc Divisiotl. Rowntree

Research Unit, Durham.LOCATION OF OFFICES BUREAU (1976) Office Relocation: Facts and Figures. Location of Offices Bureau, London.LOCATION OF OFFICES BUREAlJ (1977) Annual Report, 1976-77. Location of Offices Bureau, London.NORTHERN REGION STRATEGY TEAM (1976) Office activity in the Northern Region. Technical Repon No. 8,

Newcastle.OFFICE OF POPULATION CENSUSES AND SURVEYS (1973) Availability of Cars. HMSO, London.W ABE J. S. (1967) Dispersal of employment and the journey to work, J. Transp. ewn. Policy 1, 345-361.SOCIAL SCIENCE RESEARCH COUNCIL (1979) Survey methods to assess survey practices, SSRC SurI'. Arc/IS. Bull. 12,

11.

rfQMpn RtJ Vol ISA No S pp J91-J98 1981Pnnlcd In Grcal BrllalR

18 s l Ol'~l- 'fi11/SI/0S0J9I-01W 00/0Pcrpmon PrcSl Lld

VEHICLE SHARING FOR THE JOURNEY TOWORK BY OFFICE EMPLOYEES

P W DANIELSDepartment of Geography, Umverslty of Liverpool Roxby Buddmg, PO Box 147, Liverpool L69 3BX England

(RtCtlVtd 26 Novtmbtr 1979 In TtVlstd form 20 Ocrobtr 1980)

Abstnct-11l1s paper outhnes some spatial vanallOns In the inCidence of vehicle shanns: for the Journey to workamongst office workers at a number of locations In Brlfam The contrlburlOn of occupatIOn status and relatedfactors to the variability In vehIcle sharlnS: IS considered With reference to four case study offices and In relaLlon tothe use of private hire buses at one establishment It IS concluded Lhat the orlgmal local-speCific empiricaleVidence presented In the paper confirms the apparent lack of a umversal pattern In vehicle sharma:

INTRODUCTlON

At a time of contmulng Increases In fuel costs, cutbacksIn public expenditure on highways, and an Inexorable flseIn the cost of motonng to indiVidual car owners, Itremains prudent to explore the scope for minimizing theeffects of these change~ on our dally mobJilty for workand other purposes At the time of the fuel cnsls m theUmted States ID 1973, campaigns by national governmentand pnvate compames to encourage vehicle shanngt fortnps by workers With a Similar set of ongms and des­tmatlOns proved particularly successful, but Interestwaned as soon as the cnSls passed (Sagner, 1974) In onerecent study In the TWin Cities area vehicle sharing hasshown clear signs of diminishing after reachmg a peak m1974 (Plum and Edwards, 1980) Work Journeys are theobvIous candidate for the rromolLon of vehicle shanngactIVIty Since they are the most regular and spatiallyfocussed tTlPS undertaken by a large proportion of thecar-usmg population PrOVided that [he temporal andlocatlonal characteTl5l1cs of [np makers COinCide, andthat mdlvldual workers do not require use of a vehicledunng the workmg day, then the conditions eXist fordefining a potential vehLcle shanng population(Eash, Swanson and Kaplan, 1974) The eXIStence of sucha sub-polulatlon cannot be demed, but there remams onlylimited knowledge of speCific groups of workers wlthmthis sub-population and, In particular, any spatial vana­hons which they may reveal In thelT propensLty to sharea vehicle for the Journey to work

An opporlumty to examme vehicle sharmg from thisstandpoint has been provided by a study of the Journeyto work behaViour of office work.ers In a number ofdecentralized offices which have moved to va'rJous 10ca·tIons throughout Bntaln (Danlels, 1978, 1980,) Dunngrecent years the scope for encouragmg vehicle sharmghas been enhanced by the adoption of more flexiblealtitudes by Insurance compaOles towards the use ofpnvale vehicles for the purpose of conveymg passengerswho contnbute on a regular and negotiated baSIS to thecosts of makmg a Journey Until 1975 It was not per­mlssable for pnvate car owners to accept any paymentfor carrymg passengers In thelT vehicles. since thiS con-

tThe terms "car" or "vehicle" sharing are used tnterchan,e­ably 10 thiS paper

TRI Al IS 5--e

slttuted the use of the vehicle for "gam" Smce that time,and particularly as a result of the 1978 Transport Act, ItIS now pOSSible for owners to accept payment prOVidedthat Lt does not lead to an excess of revenue overexpenditure by the vehicle Owner Hence, those whoalready engage In, or are potential participants m, vehiclesharmg are now able to accept recompense not only forthe Immediate cost of undertaking the Journey, but alsofor mOre general overheads such as depreCiatIOn and thecost of vehde mamtamance

Such changes are helpful but It IS, of course, Importantto get the potential contribution of vehicle sharmg to thereduction of energy consumphon or congestion mtoperspectIve 1I has been shown that only 10%of all tnps to work In the United Slates, forexample are based on car pools although thiS may me tobetween 15 and 25% m some high denSity urbanareas (Dppenhelm, 1979), but 75% of these carpools only Involve two passengers The POSSibilities forImprovmg on these figures have recently been exammedby Coombe e/ af (1979), but It IS acknowledged thatthese efforts are frustrated by our superfiCial knowledgeof the determinants and mechaniCS of vehlcle-poohng,and the fact that much of the eVidence IS contradictoryThiS paper does not overcome the latter problem, butDppenhelm (1979, p 261) does suggeSl that there may besome ment In exammlng "vanous segments of thetravelling populatIOn m rela1Lon to theIT attitudes andcarpoohng behaVIOur to provLde deeper inSight Intoeffective incentive strategies" Bhatt (1975) prOVides auseful overview of vanous carpool schemes, and con­cludes that vanous company or establishment-basedoperations (mamly large scale employers) have beenmuch more successful than mare general area or city­WIde schemes of the kind proposed by PralSch (1973)

11Il SUlVEY

Establishments were used as the baSIS for collectmginformation about the inCidence and some of the attn­bUles of car shanng amongst office workers m a surveyundertaken In 1976 (FIg I) All the office workers In eachof 42 estabhshments were asked to complete a ques­tionnaire which was dlstnbuted and collected by theLremployers who sometimes endorsed the survey With aCircular of their own Any respondents who had travelled

391

392 P. W. DAN1ELS

-Glasgow J75

N.wcaslle•Sunderland•Durham

Greater London (15 officitsl

Metropolitan PlanningRegion boundary

South East EconomicPL1nning Rltgion boundary

Distanc!' from Central London -250 km

Respondent otficl!'s

2SO

...

King's Lyon

·~terborOu9h

...........

Leicester.

......'...~I.,Chl.,

Henllty atf

:' Cain:.;.:A.lderShO~ _ :R.~.gate.Maidstone

Southampton _- ~Crawle

T:... .Chl1:hesterjtc~fi.ld

~

.//

//

//I

Fig. 1. Location of case study offices and survey zones.

to work on the morning of the survey as either a pas·sengce or a driver were asked to provide information onwhether they usually shared the vehicle with others;whether the same persoo usually provided the vehicle, orwhether there was rotation; and whether they sharedonly with individuals working at the same office or alsotravelled with people who were going '0 other work­places elsewhere. In relation to the latter, respoodentswere asked to specify separately how many people.including themselves, usually travelled in the vehicle.either to the office establishment in question or to workat some other location. Some 47% of the office staff res­ponded (without follow-ups) to the main schedule. and95% of those eligible to do so completed the section onvehicle sharing. Socio-economic data and information

about where respondents had previously worked. orwhether this was their first job was also collected on theschedule.

ORGANIZATIONAL AITITUDES TO VEHICLE SHAlUNG

Previous research has shown that attitudes towardsvehicle sharing are most positive amongst largerorganizations (Bhalt, 1975; Coombe et aI., 1979; Plumand Edwards. 1980). It is therefore not surprising to findthat over 50% of the offices in the present sample did notin any way entourage their employees to consider vehi­cle sharing for the journey to work. and there is nosignificant variation according to the size of the est­ablishment. Only 16% of lhe employers activelypromoted vehicle sharing. The methods used by these

Vehicle shanng for the Journey to work by office employees J9J

orgamzatlons centred mainly on clrculars whichemphaSized access and parkmg problems In and aroundthe office bUildings concerned, or dUring and Immediatelyafter the 011 cnsls In 1973, the savmgs to be made Inour-of-pocket costs anslng from petrol consumption Afew admitted that they only advocated vehicle sharmg totheir employees dUring local cnses, such as bus companyor raLl stnkes, whlie othen pomted to the limitations oflocal public transport serVices, and suggested that theunrehablhty of services and Its effect on employee punc­tualIty could best be overcome by orgamsmg car or vanpools At one office In north east London, parkmg pref­erence was given to employees who shared their cars forthe Journey to work With colleagues at the same est·abhshment Three of the larger offices In the sample,(each emplOying more than 400 staff) Circulated newslet­ten which mcluded advertisements for hfts wanted oroffered They have found that once the momentum for avehicle sharing prolP'amme has been achieved, the sys·tern tends to run Itself and employees do not need to beremmded thiS IS In accord With [he observation byCoombe ,t al (1979) that all the scope for successful carshanng schemes rests with large orgamzatlons where the10cator board, roster and other techniques can be mosteffectIvely used The malollty of the office estabhsh­ments which did not have a pohcy, even though they did

tThe zones are as follows Zone I (GLA}-25 km, Zone 2(OMA)-2&-7l km. ZODe J (OSE)-7&-110 km. Zone 4 151­2S0km. Zone 5 2S1-375 km, Zone 6 376km Zones ~ w~l

sometimes be together referred to as the "prOVinCial zones'

admIt to an awareness of vehicle sharing for work travel,employed less than lO people There were two largeestabhshments ID thiS category where It r.nght reasonablybe expected that vehIcle shallng had been dIScussed. butIt had never been conSidered

SOME VARIATIONS IN VEmCLE SHllING

The survey offices have been grouped mto SIX zoneson the baSIS of the distance of [heir location from centralLondon (FIg I) The resultant dlStllbutlon of respon­dents and the inCIdence of car shanng for the Journey towork IS shown 10 Table I t Out of a total of more than6,000 recorded work tnps, over 36% Involved officeworkers who shared vehicles either as car drIvers orpassengers ThIS IS much higher than the figure CIted byOppenhetm (1979) as the maXimum for high denSItyurban areas, or [he 224% for salarIed employees at theGeneral Motors Research Laboratones near Detroit(Herman and Lamb, 1971) or the figure of 200% foremployees 10 the lM study (Plum and Edwards, 1980)There are at least two pOSSible reasons for the dls·crepancy, firstly, the particular circumstances at the twocase study establishments may have affected the resultsbut without recourse to data from other, Similar, est­abhshments thl3 cannot be proved Or disproved, andsecondly. even If vehicle tharmg can be shown to varysystematically accordmg to type or workplace, there IS

stili every posstblhty that the actual level of vehiclesharing will be dlfferent ID vanous parts of the country

The latter IS relevant to the relaltonshlp between urban

Table 1 InCidence of vehicle shanng for the Journey to work decel1trallzed offices 1976

Zon. Car Shar1ng by Car/Van !:riverf Not Appl1cable - ReapondentBor Pa••..,ger. on Day of Survey Valk.d or U.ed Pubhc Tt-an.port

<•• (.) No Ib) RAtlo

No ~ No ~ oil> No ~ Total

nu 21) 21 1 J6J J5 9 o 59 4J4 4J 0 1010 (lit»)

OMA JIJ J5 J 278 Jl 4 1 IJ 295 JJ J 8a6 (8)

OSE I,oJ 4' 8 2810 JO 2 1.t.2 254 27 0 '" (9)

4 126 J5 8 72 205 1 75 154 4J 8 J52 (4)

5 152 J9 6 H4 29 7 1 J' H8 JO 7 )810 (2)

6 1085 1,0 1 285 10 5 J 81 1))6 "4 2706 (5)

Total' 2292 J6 5 1)96 22 2 1 65 2591 " J 6279 (42)

Note. 1 Only pa.Bengers or drivers of cara, van., threewwheeleraor .otor-cycle. on the ~orn1ng of the day of the aurveywere aaked to lndicate whether they part1c1pated 1n vehlcle.har1ng

2 Non_respondents by zone a. follow.

1 : 19 J ,.. ),8 5 = 62 " 29 4 • 6 6 " )J

Source Follow-Up Survey 1976

394 P. W. D,<\NIElS

density and the level of vehicle sharing alluded to byOppenheim (1979). The incidence of car sharing in·creases at the office establishments furthest from Lon­don (in the provincial lones), even though several largeoffices in these .areas are located in relatively small urbanareas with less than 100,000 population. Office employeestravel to work from settlements widely distributed in thesUITOlmding r~gion, however, and these circumstancesmay be more conducive to vehicle sharing than in theGreater London Area (G LA) which is the only zonewhere the ratio of car sharing to non-car sharingemployees is below 1.0. [n gener<ti, the ratio increasesoutward's to the extremely high value of 3.81 in zone 5and 6 which includes Durham, Darlington, Newcastle.Sunderland and suburban Glasgow offices. Some 80% ofthe journeys to work by car drivers or passengers in thiszone were undertaken with somebody else comparedwith 37% in the Greater London area. Some care must betaken when making this comparison. however, since tripsto work by private car comprise a smaller proportion ofa1l trips in the privincial zones than elsewhere; indeed41% of the trips in these zones were made on foot orused public transport. Thus, the contribution of vehiclesharing to a reduction in congestion or diverting publictransport users is most clearly expressed in the OuterMetropolitan Area (OMA), and the Outer South East(OSE) where private transport dominates modal choicefor the journey to work of office staff.

The occupation status and sex of respondents impartsfurther variation upon the broad spatial contrasts invehicle sharing. As a general rule. female office workersare twice as likely as males to share a vehicle for thejourney to work, even though the proportion travelling inthis way increases from 29% for males in Greater Lon­don to 66% in provincial zone 6, and from 52% forfemales in Greater London to 86% in zone 6. The zonalcontrasts in participation are further reflected in dis­aggergated figures for four occupation groups. Althoughthe differ-ential is rather narrower for females, managerialand professional. office staff are only half as likely toengage in vehicle sharing as supervisory or. in particular.clerical workers. This distinction is important becauseeven if the growth of clerical work in offices has sloweddown in recent years as new technology is introduced.they will probably remain the largest single group ofoffice workers for some years yet. The decisions whichthey make about vehicle sharing are therefore likely toremain critical to the overall improvement in ac­cessibility to a building or an office centre. as well as to areduction in the consumption of energy.•But the scopefor inducing a higher level of ve~icle sharing amongstthose clerical workers already travelling to work as cardrivers/pa~sengers must be limited since, particularlyoutside Greater London, over 70% of the female clericalstaff (almost 88% in zone 6) were already involved. Tosome degree this presents a dilemma because any furtherincrease in vehicle sharing may be at the expense ofwork trips using public transport which. in most cases.requires more not less patronage.

There are a number of reasons for the underlyingvariations in vehicle sharing activity which have been

briefly outlined in Table I. The proportion crf managerialand professional staff tends to be lower in offices outsidethe. South East and, related to Ihis through incomedifferences, so does the overall level of car ownership.These two factors alone may, on the one hand, dis­courage vehicle sharing because senior office staff havebeen shown to travel longer distances and to occupyspatially dispersed residential locations, or on the otherhand, will encourage as much sharing as practicableamongst lower income oftke staff in areas where publictransport often provides an inadequate alternative forwork travel from awidely distributed setof settlements (andoften over substantial distances in the provincial zones).Labour turnover is lower in decentralized offices .especial!youtside London. and this provides a better opportunity forpotential participants in vehicle sharing to identify otherswith similar travel schedules. This is likely to be particularlyimportant in the provincial zones amongst clerical workerstravelling from a variety of smaller settlements somedistance from the town in which their office is located. It isalso likely that attitudes towards vehicle sharing varyconsiderably according to occupation status and the socialmilieu of office workers. Some indication of this' is providedin Plum and Edwards (1980).

Average vehicle occupancy rates, which Coombe et al.(1979) show to vary between 1.32 and 1.49 in Leeds andBradford during the morning peak period, also revealsubstantial differences between zones. Of the respon­dents who shared a vehicle on the day of the survey,66% indicated that· they travelled with colleaguesemployed at the same office and this represents anoverall vehicle occupancy rate of 2.77 (Table 2). Thiscompares favourably with the rate of 2.8 quoted by Bhaltfor McDonnel1 Douglas Aircraft Corporation employeesIn SI. Louis (Bhatt. 1975). The socio-economicdifferences in vehicle sharing and the higher participationrates in the provincial zones lead to higher occupancyrates which exceed 3.0 in zones 5 and 6. Car sharing notonly helps to reduce vahicle convergence on the est­ablishments in the sample, it may also contribute to sometrip reductions by vehicles with other destinations. Anumber of office workers shared with individuals whowere travelling to other destinations and the averageoccupancy rale (Tab[e 2) for this group is similar to thatin Leeds and Bradford (Coombe el al.. 1979). Contrary toexpectations. there is no systematic variatio'n in theoccupancy rate for this group, The precise reasons forthis are unknown but it is probable that the explanationrests with factors such as the pattern of workplaces inthe areas to which shared trips are made. the degree towhich members of the same household are employedadjacent to or between the origin and destination of theprincipal trip maker. or the exte·nt to which individualsfollow work schedules which allow them to collect carpool participants from other locations without excessivedelay.

An additional factor which might reasonably beexpected to influence the leve[ of vehicle sharing activityis the increasing use of flexible working hours in offices(Danie[s. 1980b). Employees nor involved in suchschemes should. in theory, find it easier to come to

Vehicle sharing for the Journey to work by office employees 395

Table 2 Extent of vehIcle shanng Wllh collealiues al same office, 1976

Zono Tot.al Car No Sharlng 1 ~ 0' A~rage Vehl~le

Sharlng wlth Colleaguee Total Occupancy

GLA 21) 10) 48. 2'0 (1 1t-5)J

OKA )1) 176 56 2 2 29 (l 2)

OSE ~) 252 62 5 2 62 (1 IKI)

• 126 55 .) 7 277 (l 4.2)

5 152 109 71 7 ) )2 (1 )1)

6 1085 809 7' 6 ) 1) (1 4.9)

Total 2292 l501t, 65 6 2 77 (l 40)

Notee nllue flgures slightly understate t.he degree ofsharlng "nth colleaguee since a .all nUllber ofreepondents falled to answer thLS part of the quest10n

2 Respondents were allked to lndlcate how .lllUlycolleagues t.hey ehared vlth, lnclud1ng themselvesAveraga veh1cle occupancy lS, therefore, totalpereone, lncludlng drlvers, dLvlded by nuaber ofrespondente aharing wlth colleague.

) Based on nu.lber of otherll .hared W1 th who weretravell1ng to locatlons other than the decentrallzedofflce

Follow_Up Survey, 1976

Table) Vehicle sharing by employees on ftexlble hours 1976

Zon. Proport1on of E-ployee. Travelling to Work by ear/Van Engaged .nCar Sharlng

On Fle:nble Not On Flexlble Tot.lHours Hours

GLA 35 9 (156)1 .) 5 (2)1 66 (J6 9)2-

OKA 48 6 (27) 61 1 (175) 266 (5) 0)

051 B2 0 IB9) 66 7 I) 75 (81 5)

• 100 0 (2) 52 6 (J8) 22 ('5 0)

5 59 9 (2lt2) 2) 5 1!7l "9 157 5)

6 B1 7 (1106) 6) B (H,1 ) 994 (79 7)

Notes Denot.s total _ployee. on flexible hours or not on!lexlble hour. who travelled to work by car/van onthe day of the survey

2 Total and proportlon engaged 1n car sharing

Source ~0110w-Up Survey, 1976

acceptable travel arrangements because of the com­cldence of thelT starting and finIshmg times at workSuch expectations are confirmed for the offices m theGlA and OMA but contradicted In the remaining zones(Table 3) It seems that some office workers may beprepared to sacnfice the greater flexlblhty afforded by

the freedom to arnve and leave work outside a defined"core" penod In the mterests o( the savmgs In vehicleoperatmg costs or the opportumty to travel to work Withfnends, provided that agreement can be reached onSUitable travel arrangements Many of the office !taft' In

the provincial zones who are working ftexlble hours are

396 P. W. DANIELS

Table 4. Summary data for case study offices

Variable

Total E:lII.ployees

Location

New MaIden Southampton Leicester DurhalllGLA OSE Zone 4, Zone 6

584

total respondents

Car driver/pass. trips (~)

Car sharing ('lll)

r, 1

Car sharing/occupation

Car sharing/car ownership

Car sharing/trip distance

Car sharing/trip time

Car sharing

Car sharing

others

214

11. lit,

11.2

36.1

30.6

174

48.9

2.67

5.94

1.11

7·50

6.6

7.6

27.)

159

50·9

12.)1-

3.52

2·75

'·39

9.8

9.2

26.6

2)·5

1051

26.))

9.8

8.9

2).2

18.8

Notes: 1. For null hypotheses, a•• texx.2. Value. in bradtets denote num/)er of ottice workers

participating in car sharing.

Values for X2 significant at .05 level.

Source: Follow_Up Survey, 1976.

clerical workers and since many of them travel longerdistances than average they clearly continue to value theadvantages which follow from car sharing.

VEHICLE SIIAIUNG AT FlJUR CASE STUDY omcF.'lSome of the general observations derived from the

zonal data can be examined in more detail with referenceto four office establishments at contrasting locations(Tahle 4). It has already been implied that the occupationstructure of an office will define the scope for vehiclesharing activity. Hence the hypothesis that there is nodifference in car/van sharing with respect to occupationstatus can be rejected (using the X' test) at the 0.05 levelat three of the case study establishments; the exceptionis the Southampton office where the number • officeworkers not involved in sharing is small and thus makesit difficult to use X'. The hypothesis is rejected at NewMaIden even though 36% (11) of the work trips bymanagerial employees involved shared vehicles and thisis much higher than the 4-7% elsewhere. A possibleexplanation for this situation is that a large number ofthese employees had previously travelled to work incentral London for the same company prior to relocation

and since they have remained resident in adjacent areasof south west Surrey they have decided to share vehiclesto the new suburban location.

Car ownership does not exert a consistent influence onvehicle sharing (Table 4). It is only possible to reject thenull hypothesis that there is nO difference in carlvansharing with respect to car ownership at the offices inNew M81den and Durham. The high overall level of carownership amongst the New Maiden office workers. whoalso comprise an above average representation ofmanagerial and professional staff, is an important factorat that location but at Durham. where household carownership is much tower, a large proportion ofemployees from such households also share their vehi­cles with a large number of passengers. The latter out­number car driver trips by two to one at that office. Themajority of shared trips originate from one--car house~

holds (between 69 and .78%) although at New Maiden andSouthampton over 25% of the shared trips involve officeworkers from two-car households.

The incentive to share vehicles for the journey to workis likely to be greatest for those employees who haveintermediate or long distance trips and spend more time

Vehicle sharmg for the Journey lO work by office employees 397

than average to reach their destinatIOn This needs to bebalanced, of course. agamst the reduced pOSSIbIlity ofproximity to other possible partIcipants as the distancefrom the workplace Increases unless the settlement pat­t~rn, as In parts of zone 6, determmes that someagglomeration of the labour source. particularly for verylarge office estabhshments, IS mevltable There IS eVI­dence m the case study data that office workers engagedm vehlc1e sharIng do travel further and take more Elmethan other office wor,kers who use pnvate transport(Table 4) But agam, lhe hypotheSis that thereIS no difference m carfvan sharmg With respect lo trIpdIStance can only be rejecled at New Maiden andDurham and the same IS true of a parallel hypothesIs fortrIp times Therefore at New Maiden, the average dls­lance travelled by vehIVle shanng office staff IS 174 kmcompared WIth just 11 2 km for non-car shanng staffSome 53% of the shared journeys exceed 10 km mlength A slmtlar distinction OCcurs at Durham where44% of the car sharmg tnps exceeded 10 km although theaverage dIStance Iravelled (98 km) IS only margmallyabove that for other prIvate transport users In general, It

seems that vehicle sharing IS most lIkely to take placewhere Journeys to work are above average length forestablishments m the area, or at office estabhshmentsWith large numbers of staff. often In related occupations,resId109 10 Similar settlements or suburbs of a city

PIUVA'n HIR.E BUSES

At two of the offices Included In thiS study. one to

surburban Glasgow and the other 10 Durham. vduclesharing was not confined to pnvate cars and vans but

Included the use of pnvate hire buses orgamzed at theInltIaltve of the employees Bhat! (1975) has referred tosucb services as subscnptlon buses and he suggests thatthey are generally substantially better than public servicebuses In terms of access, comfort, relIabilIty, door to­door tnp times and overall Journey COSts may only bemargmally hIgher than for car-based Journeys to work Ithas been estimated that total door-to-door times forprtvate hlTe buses or other vehicle shanng tnps are onlysome 25% higher than for car drIver Journeys On lheother hand, such services are infleXible and costs may Infact fluctuate conSiderably accordmg to ftuctuatlons In

user levels determmed by employee turnover, changIngpatterns of reSidence or dissatIsfaction With thearrangements OvercrowdlOg on some pubhc serVIceroutes can also act as a stimulus for prtvate hlTe, thiS wasCited as an Inportant factor for Durham office stafftravelling (ram seUlement~ between and beyond WlltonGIlbert several mIle, north of the cuy The effecI ofpnvate hire buses on potentIal vehicle convergence onbuIidmgs IS likely to be greater Ihan [or car shanng,especl3l1y If some office workers who would havetravelled m a car pool deCide to use the pnvate hireservice However, there must be a hmlt to which theadvantages of such services can be directed before theyare outweighed by the dIfficulty of devlSmK routes whIchbnng together enough subSCrIbers WIthout creatmgexces:!Ive Journey distances and waltlOg!m transit times

Nevertheless, almO'st 13% of the respondents at theGlasgow office travelled to work ID pnvate hue buses(Table 5) If It IS assumed that thIS sample stat"t1c ISapplicable to the total labour force of the establishment,

Table 5 Some attributes of private hue bus triPS for the Journey to work, GI:ugow office 1976

Total) Prlvate Bua2

Share of PrivataTrlpa Trlpe (~) Bu. Tnps (,,)

Sex Males 479 10 6 29 9'Fe_al•• 908 IJ , 70 1

Occupatlon Managerlal J9 2 6 o 6ProleaalonalSupervlaory 170 11 1 10 9Clerl.cal 1190 IJ J 885

Car Ownerahlp No Car "6 12 4 '007One ear 569 12 5 ,,6Two ... Carll 87 4 a 3 ,

Tr1P TlIne ." 17' 2 J 2 ,(1II1ns) 16 - '5 570 9 6 Jl 8

)5 - 59 481 20 6 "'J60 - 89 I" JJ 1 11 5, 90 47 146 J 8

TriP Dllltance < J 289 J 2 , 7

(Itln) J - 10 590 11 1 J7 611 _ 22 J84 22 , "'6:2) - 48 124 17 0 11 ,

> 48 2J 4 5 o 6

Notell Percentage Valuell s~ to lOO for each var1able2 Private hire tr1ps a. percentag4 of all trlps (12 5")J Absolute nu.ber of prlvate hlr~ trlPS 1n s~ple (157)

Source Follow_Up Survey, 1976

398 P. W. DANIELS

then it is likely that approximately 650 workers parti­cipate. At a vehicle occupancy rate for private hire busesof 42 persons this is equivalent to at least 15 serviceswhich. assuming that the majority of the employeesinvolved would otherwise commute by car, substitute formore than 400 car/van journeys (assuming a vehicleoccupancy 'of 1.49) or over 200 such trips if the zonaloccupancy rate (3.13) is utilized. These are, of course,likely to be upper estimates but they provide an in4

dication of- the potential of private hire services, alongwith public bus services if office workers could be per­suaded to use them. for reducing peak hour traffic loadsand parking demand at trip destinations.

In this instance. female office staff seem more likely touse the service than wouJd be expected from theirrepresentation in the sample. They make 70% of the tripsby private bus as opposed to 65% of all trips (Table 5). Itis therefore not surprising to find that the principal usersof this method of work travel are clerical workers whomake 89% of the total trips by private hire bus. Officestaff entering the labour force for the first time, many ofthem not yet having access to their own car, also seemmore prepared to consider this alternative, Perhaps atthe time that the scheme was brought to their attentionthey did not possess sullicient knowledge of the relativecosts and benefits of competing modes, principally publicbus services. It is also noteworthy that over half of theGlasgow participants are from one-car households, afigure which is marginally higher than the overall shareof these households in the sample.

Users of the private hire service also tend to spendmore time and to travel further to work than the averagefor all .the trips in the sample (Table 5). Such servicestherefore appear most practicable for work trips forwhich the likelihood of a direct public transport route(which does not involve transfer or waiting times be­tween services) is low. The fact that the share of privatebus trips in the 35-39 min and 10-22 km range is almosttwice the overall proportion of 14% is also likely to berelated to the threshold of cost effectiveness belowwhich it would not be worth engaging a private hire buscompany to provide a service.

Since this represents just one case study the con­clusions relating to the value of private hire bus opera­tions must be very tentative, A similar, but much moreinformal, arrangement which involved a smaller propor·tion of the total workforce operated at the Durham officewhile some of the other offices in the suryey providedspecial "mini-bus" services tor their employees. Thesewere not systematically examined at the time. It seemsclear. however, that on the basis of the evidence fromlhe Glasgow ollice, Ihis form of para-Iransit for thejourney to work, particularly its potential impact on largeestablishments with several hundred or more employees,would repay further study.

CONCLUSION

With reference to a specific type of land use in urbanareas, variations i'n car sharing at various locations

throughout Britain have been identified and related to anumber of socio-economic parameters and trip charac­teristics of office workers. It is clear that in purely.empiricalterms car sharing constitutes an important, andprobably increasing, element in the journey to work ofoffice workers and along with the use of private hirebuses it may pose a further threat to the use of publictransport. Since the resource implications of this threatare to some extent cushioned by higher private vehicleoccupancy rates it may be more acceptable than directtransfers from public transport modes to car driverjourneys, Further work on the behavioural aspects ofvehicle sharing and the effect of inducements needs to beundertaken before a full assessment of its potential as analternative method of work travel can be- properlyunderstood,

In common with previous studies, the results outlinedhere are inconclusive; indeed they contradict some of theearlier findings such as those reported by Oppenheim(1979). Perhaps this indicates that decision-making aboutvehicle sharing is more complex than is commonly bel­ieved and is subject to a wide range of subjective/in­tangible factors of the kind discussed by Plum andEdwards (19g0). This paper has added some original,local-specific. empirical evidence about car poolingwhich confirms the apparent lack' of a universal pattern.

Acknowledgements-This paper is derived from research com­missioned by the Departments of Environment and Transport.London. The interpretation of the data is solely that of the authorand does not necessarily represent the views of the Departments.1 would like to acknowledge the assistance of A. W. Duffelt withthe preparatwn of the data used in the paper. The tables arereproduced by permission of Her Majesty's Stationery Office.

REFERENCES

Shatt K. W. (1975) Subscription buses and car pools. In Para­Transit: Neglected Options for Urban Mobility (Edited byKirby R. F: et al.), pp. 215-250. The Urban Institute, Washing­ton D.e.

Coombe D.• Foster M. and Riley T. (1979) The case for carpooling and staggered hours. Surveyor 153, 13-16.

Daniels P, W. (1978) A Follow-Up Study of the Journey to Workat Dtcentralized Offices in Britain Vols rand 11. Departmentsof Environment and Transport, London. (Limited circulation).

Daniels P. W. (I980A) Office Location and the Journey to Work.Gower Press and Retail Planning Associates, Farnborough.

Daniels P. W. (19808) Flexible hours and the journey to work tooffice establishments. Transpn Plann Tech. 6, 55-62.

Eash R. W.. Swanson A. and Kaplan M. (1974) An analysis andevaluation of alternate schemes to increase auto-occupancy.Transpn Res. 8, 335-341.

Herman R. and Lam T. (1975) Carpools at a large suburbantechnical centre. ASLE Proc. Transpn Eng. J. 101, 311-319.

Oppenheim N. (1979) Carpooling; problems· and potentials. TratQ. 3J. 2l3-262.

Plum R. A. and Edwards J. L. (1980) Attitudes towards ridesharing; 3M Center case study. Trilf. Q. 34. 287-304.

Pratsch L. W. (1973) Calpoof and Buspool Matching Guide. U.S.Department of Transportation Federal Highway Ad·ministration, Washington D.C.

Sagner 1. A. (1974) The impact of the energy crisis on Americancities based on dispersion of employment, utilization of transitand car pooling. Transpn Res. 8, 307-316,