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SUBMISSION ID TP.36: TRAFFIC MANAGEMENT OF MEGA

INFRASTRUCTURE CONSTRUCTION PROJECTS - ROLLING ROAD

BLOCK TECHNIQUE

Dr. Baha Alshalalfah1, Yazan Al Banna

2, Sami Al Hawish

3, Dr. Jalal Nafakh

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1 Transport and Infrastructure Director, SETS Int., Amman, Jordan

balshalalfah@setsintl.net 2 Senior Transport Engineer / Project Manager, SETS Int., Riyadh, KSA

yalbanna@setsintl.net 3 Senior Traffic Engineer, High Commission for the Development of Arriyadh (ADA), Riyadh, KSA

hawishs@ada.gov.sa 4 Chief Transportation Planner, High Commission for the Development of Arriyadh (ADA), KSA

nafakh@ada.gov.sa

Abstract

The Saudi Arabian government is investing more than $22 billion to build a Metro system in the

Capital Riyadh, with a total length of 176 km across 6 lines and 85 stations. The metro network has been

under construction since 2013, and is expected to be in operation by 2019. One of the biggest challenges

that faced the authorities early on is how to manage traffic during the construction period especially that

the metro lines run along some of the busiest corridors in the city.

Line 6 of the network runs along different corridors with different characteristics and land uses:main

freeways, major and minor arterials, collectors, as well as residential and commercial areas. To

accommodatethese variations,the route sections and stations have different types: at-grade, shallow

underground and viaducts. The construction methodology andprogram requirespecific temporary traffic

plans to manage traffic for each type of route section or station.

Parts of Line 6 run along 3 main freeways as viaduct sections: Eastern Ring Road (ERR), Northern

Ring Road (NRR) and Airport Road, eachwith a posted speed 120 km. These freeways are some of the

main expressways in the city, linking east to west and north to south. Pre-Cast concrete segments

wereselected as the construction methodology to be applied on most of line 6 sections; specifically,

Precast Segmental Method (PSM) and Balance Cantilever Method (BCM) were applied at the viaduct

links that are crossing the NRR and ERR respectively.

Temporary Traffic Control Plans (TTCPs) were applied and operated to facilitate the construction

stages of these viaduct sections. Parts of the TTCPs require occupying1-2 lanes temporary for a period of

5-6 hours on several nights to transport the concreteSegments. To maintain traffic safety on these main

freeways during the temporary night closures, Rolling Road Block (RRB) technique was applied to lessen

the impacts of decreasing the operational speed(and associated shockwave) of the freeways from 120km/h

to a complete stop. This technique was applied and operated successfully more than 10 times.

This paper presents the benefit of applying RRB technique including a benchmarking exercise against

projects of similar nature/scale, adopted methodology, challenges faced, as well as the results after the

implementation of the plan. This success story could be a good case study for forward thinking of

managing traffic in mega infrastructure and urban transport projects especially on major freeways.

Keywords:JTSC2017, Jordan, Amman, Traffic Safety, Conference

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Introduction

Riyadh City is the capital of the Kingdom of Saudi Arabia, and is one of the largest cities in

the Middle East with a population of around six million, which is expected to grow to 9.5 million

by the year 2025 [1]. Recent growth patterns and future forecasts indicate that Riyadh will have

very high population growth rates, which will lead to an increase in the demand for travel on its

roadway network and transportation system. The daily vehicle trips in Riyadh in 2015 were

estimated to be over seven million trips/day, with more than 100 million kilometers travelled

daily [2]. Travel forecast models, developed and maintained by the authorities in Riyadh,

revealed that the continuous growth of the city would result in more traffic congestion on the

city’ road network, which could affect the economic viability and sustainability of the City if not

addressed sooner than later.

In December 2011, the cabinet approved all phases of the public transport project in Riyadh

(metro & buses) based on the related studies

conducted by the High Commission for the

Development of Arriyadh(ADA) in

cooperation with the concerned authorities to

find comprehensive solutions to the traffic

congestion problem in Riyadh city.

This plan aims at providing all population

groups with suitable public transport services,

diversifying the transportation means in the

city effectively and appropriately, in addition

to keeping the use of private cars within the

minimum limits.The project will be of great

benefit to Riyadh traffic, economy, society

and environment. Moreover, it will provide

the city with a giant public transport system to

meet its existing and future needs, Figure 1.

Figure 1: Riyadh Public Transport Program Plan

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Sensing this urgency, in 2011 the government of Saudi Arabia allocated a budget of more than $23

billion to build a full Metro Network in Riyadh. The project is managed by the Arriyadh Development

Authority (ADA), aims to provide feasible and divers mobility options for people in the city of Riyadh.

The total length of the Network is close to 176 km across 6 lines and 85 stations [3], covering most of

the City of Riyadh, linking the city center to universities, the international airport, a newly built financial

district and major commercial areas as shown in Figure 2.

Figure 2: Riyadh Metro Lines

The Metro project is likely the largest urban transport project in the world during its construction

program, incurring a lot of pressure on the city infrastructure and operation during the construction phase.

Construction of the project started in 2013 and is planned to be completed in 2020.

The construction and delivery of the Metro Project was awarded to 3 different Design-build

Contractors (DBC) as follows:

Package 1: BACS Consortium was awarded the design and build of Lines 1 and 2 with a

total length of 63.3 km of network.

Package 2: Arriyadh New Mobility Consortium (ANM) was awarded the design and

build of Line 3 with a total length of 40.7 km.

Package 3: FAST Consortium was awarded the design and build of the remaining 3 Lines

(lines 4, 5 and 6), covering a total length of 72.5 km.

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To facilitate the interaction between the owner of the Project ADA and the DBCs, two Project

Management / Construction Management teams (PMCMs) were retained by the ADA as the owner

representative and to act as the interface between the DBCs and the ADA. The organizational chart of the

Riyadh Public Transport Program, as described above, is presented in Figure 3 below:

Figure 3: Organizational Chart of the Riyadh Public Transport Program

Due to the very tight and demanding construction schedule of the Riyadh Metro and the fact that many

construction activities affecting the roadway network are going to take place at the same time, there was a

great focus on traffic management during construction to keep the city moving. As such, and to ensure the

smooth implementation of the project and to minimize the adverse impacts on traffic conditions in the city

during the Metro construction phase, each DBC and each PMCM were required to hire Traffic

Management Consultants to develop traffic management schemes under which each Metro line will be

constructed. The foremost objective of these schemes is to minimize the adverse impacts on traffic

conditions in the city during the construction period.

Temporary Traffic Management Plan TTCP

In coordination between the PMCM and DB Traffic Teams, a TMP for Metro Lines were prepared.

The Plan sat out, among other items, the overall project timetable, construction methods, proposed major

traffic management schemes (TTCPs) anticipated, and initial logistics plan. The information provided in

the TMP identified what constraints may need to be applied in terms of construction timing or method,

where it has a bearing on traffic management. The TMP also identified hard and soft mitigation measures

which may be required to mitigate the expected adverse traffic impacts.

Throughout this process, the Traffic Team was in continuous coordination and liaison with both the

client (ADA) and the construction team to make sure that the both parties fully understand the

requirements of the elements of the traffic management plans begin developed by the traffic team to avoid

any surprises.

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The TMP sat out the following Traffic Impact Assessment (TIA) procedure to be followed in

developing the alternatives for traffic management schemes:

Step 1 – Define Study Area and Site Appraisal

Step 2 – Define Traffic Surveys’ Work

Step 3 – Analyse Existing Traffic Conditions

Step 4 – Traffic Modelling Work

Step 5 – Analyse Impact of Construction Works on Area of Influence of Project Site

Step 6 – Develop Mitigation Measures

Therefore, a Comprehensive Traffic Management Plan for each line was developed, implemented and

operated, includes operating Rolling Roadblock technique at many locations, in particular Metro Line 6,

based on state-of-the-art traffic management practices, supplemented by innovative and outside the box

thinking. The Plan, was implemented with great success and was well received by the general public in

addition to key stakeholders.

This paper presents the thinking behind the development of Rolling Roadblock technique, the process

followed, challenges faced, adopted methodology, as well as the results after the implementation of the

plan. This success story could be a good case study for forward thinking of managing traffic in mega

infrastructure and urban transport projects.

Methodology

Line 6 length is around 20.5 km, including 5 stations (2 are transfer stations), with one depot common

with line 4 and two main areas for park and ride. The tunnel section is 2.6 km, at grade section is 1.5 km

and Viaduct is 16.3 km, Figure 4 and 5.

Figure 4: Line 6 Alignment

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Figure 5: Line 6 Profile

Construction Location

The section between cut and cover and station 6D2 which located within the Airport Rd, Eastern Ring

Road ERR and Northern Ring Road NRR is considered as the most critical section, since these highways

are connecting north with south and east with west and via verses, with high daily traffic volume.

ERR and NRR have 4 lane in each direction, the posted speed is 120km/h and the operation speed

increases at off-peak to reach the posted speed. The daily traffic volume within NRR is 100279veh

Westbound and 68227 veheastbound, at ERR the daily traffic volume is 22091 veh northbound and 15422

veh southbound.

Construction Method

Pre-Cast concrete segments Method was selected to be applied on most of line 6 Viaduct sections,

there are many reasons for this selection, which could be summarized as; The need of crossing highways

roads,Less time during construction, Improve Quality Control and Quality Assurance, Less impact on

traffic network, Less area needed for construction, Temporary effects (relatively), Easy to control and

Less risk than other methods. Precast Segmental Method (PSM) and Balance Cantilever Method (BCM)

were applied at the viaduct links that are crossing the NRR and ERR respectively, Figure 6.

Figure 6: Line 6; Precast Segmental Method (PSM) – left, Balance Cantilever Method (BCM) - Right

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Construction Requirements:

The requirements could be summarized from traffic point of view as below and shown in Figure 7;

Segments transportation Plan.

Segments lifting Plan which need 1 and/or 2 lanes.

Occupation 1 or 2 lanes temporary during nights.

Occupation 1 or 2 lanes for long time relatively.

Full closure for slip ramp and loops at interchange.

Full closure for main road and divert it to another route.

To implement and operate each of above, a Rolling Roadblock Technique was been selected and

operated, to maintain high level of traffic safety conditions.

Figure 7: Examples of Construction Requirements

Rolling Roadblock (RRB)

A rolling roadblock is a method of temporary traffic control that is used to slow or stop traffic as a

means of temporarily removing traffic from a roadway. The rolling roadblock closes all lanes of traffic by

using pacing vehicles to create a gap so that construction activities can be performed. Rolling roadblocks

are used for short term work where long term road closures using temporary traffic control devices

(TTCD) are not needed [4].A rolling roadblock requires one blocking/pacing vehicle per lane of traffic, a

clearing vehicle, and an advance warning vehicle.

In our case, only Blocking/pacing vehicles were used, since the distance between the construction

work and the line of Blocking/pacing vehicles was decrease as possible for increasing the traffic safety

conditions. ADA assign Mawqif Company to manage the parking within the area of TTCPs, and their

patrols were used also for the operation of Rolling Roadblock.

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Rolling Roadblock Planning

Those planning, designing and maintaining a roadway considered when a rolling roadblock

wasoperated within Riyadh Metro Project:

Specifyconstruction activities like segments lifting, where they will occur; at first or/and second

lane, times of day like (1:00 to 6:00) am or (4:00 to 9:00) am – Ramadan Period, normal dayshad

been selected for simple work and weekends for critical work.

Check all construction equipment’s, like cranes to reduce the risk of failure.

Determine the parties who had the responsibility like DB, Traffic Police, Mawqif, PMCM, ADA

representative.

An emergency plan was developed to handle traffic for some unforeseen circumstance such as

work requiring considerably more time than expected, an accident on the work site.

An advance planning meeting with all participants was held two weeks in advance to define

everyone’s responsibilities and make sure those activities required for accomplishing the task will be

in place for the event.

Establish the lines of communication between the parties involved and determine the lead

coordinator and points of contact for others participating in the actual rolling roadblock.

A final meeting among the participants before the activity was held to make sure all requirements

for the rolling roadblock had been implemented.

The rolling roadblock was normally performed by law enforcement officers in patrol cars Riyadh

traffic police (RTP), in coordination with Mawqif patrols, also DB provide his traffic safety cares

during the operation.

Training the man power, drivers and labors and determine the leaders of each team, also conduct

a test to estimate the time needed for each step.

Conduct a check list includes the recourse needed like barriers, warning lights, etc., equipment’s

like traffic safety cars and attenuators and man-power.

ADA – public relation department announced through media channels that there are works during

specific nights at the locations, and that increase the driver’s expectations, also the VMS within ERR

and NRR are used for the same reason.

Inform Civil Defense and General Security Department with all details to adapt with any

emergency causes.

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Executing Rolling Roadblock

Site Preparations

1- Site meeting before the operation was conducted in presence of all parties, Figure 8.

2- DB had all materials on site that were required to complete the work activity during the time

allotted for the rolling roadblock.

3- Check the availability of all needed recourses.

4- Check the lactation of DB convoy for installing the temporary traffic measures, and its order

should be accordance to the type of work, the attenuators shall be the last car, Figure 8.

5- Check the readiness of closing the accesses to highway within the construction area, to assure that

no traffic is on the highway and a gap has been created.

6- Check the communication lines within team leaders and their staff.

7- Determine the station of lead coordinator of the rolling roadblock to facilitate his mission during

the operation.

8- Determine the safety check point, the point which RRB fleet cannot pass through it until lead

coordinator make sure that all construction activities had been done.

Figure 8: Site Preparation Activities

Initiating the Operation

Four main groups were organized for this mission;

A. RRB Fleet which includes DB safety Cars, Mawqif cars and RTP patrols, initially this group had

been collected around 10 km in advance. First Mawqif cars then DB cars then RTP patrols.

B. Traffic Safety fleet which includes DB safety car, traffic safety tools and equipment’s and

attenuators, initially this group had been collected at the shoulder or the near access to highway.

C. Accesses blocking group, includes RTP patrols and Mawqif cars, initially this group had been

located at accesses which needed to be closed.

D. Lead coordinator team, which located at the area that each activity could be seen by him.

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The operation steps could be summarized as below:

1- Lead coordinator ordered group A to start driving within the highway with its operation speed.

2- Group A gradually take place in highway and then they block the highway with its operation

speed, and they informed the lead coordinator for that, and then reduce their speed gradually to

reach 10 km/h.

3- Lead coordinator ordered group C to block all necessary access.

4- Lead coordinator investigate the highway to make sure that there are no any vehicle and the

highway is cleared.

5- Lead coordinator ordered Group B to start implementation of the temporary traffic measures,

during that group A will reach the safety check point, and waiting Lead coordinator order to

proceeds.

6- Once the lead coordinator check that the temporary traffic measures were installed, he ordered

Group A to proceeds the safety check points with low speed to reach the construction area and

guide the drivers to the diversion.

Figure 9: RRB Operation Stages

Stage 3 Stage 4

Stage 1 Stage 2

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Figure 10: RRB Main Stage

Finalizing the Operation

Monitoring the traffic condition during the first hours of operation is very important, also keeping the

attenuators inside the construction area and the traffic safety cars at shoulder with switching on their

emergency light will help the drivers to reduce their speed and to be more familiar with the traffic

diversion.

Figure 11: RRB Finalizing the Operation

General Comments and Recommendations

Rolling roadblocks are used for short term work on high-volume/high-speed urban and rural

freeways and other multi-lane access controlled facilities where traffic would normally flow

unimpeded in the absence of other traffic control devices.

A rolling roadblock typically slows traffic while the work is being done, which increases safety

and reduces the number of crashes caused by roadway construction activities by allowing traffic to

continue moving at a reduced speed rather than coming to a complete stop.

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Rolling Roadblock could be applied for (30 – 60) mins, if more duration needed, another methods

are more appropriate.

If the timing and pacing of the operation is successful, traffic should not have to stop. But if the

work takes longer than expected or the pacing was off speed, the pacing vehicles may have to stop

traffic until the work is completed.

Rolling roadblocks may be used on other roadways, but in most cases other traffic control

techniques may be more appropriate.

The timing of the rolling roadblock should be coordinated with any large traffic generators in the

area, such as hospitals or large manufacturing companies, to avoid interfering with any shift changes

that might create spikes in traffic.

When a rolling roadblock is used, the use of law enforcement officers and vehicles is more

effective than using other vehicles because motorists tend to obey and respect law enforcement

vehicles more than agency or contractor vehicles.

If other vehicles are used as pacing vehicles instead of law enforcement, they may need to

straddle the lane and shoulders to effectively block passing on the shoulder by aggressive motorists.

If there are numerous interchanges within the limits of the pacing operation, the operation may

have to be shortened and the rolling roadblock could become a method of simply stopping traffic

instead of slowing traffic.

Summary and Conclusions

Line 6 of the network runs along different corridors with different characteristics and landuse: main

freeways, major and minor arterials, collectors, as well as residential and commercial areas. To

accommodate these variations, the route sections and stations have different types: at-grade, shallow

underground and viaducts. The construction methodology and program require specific temporary traffic

plans to manage traffic for each type of route section or station.

Parts of Line 6 run along 3 main freeways as viaduct sections: Eastern Ring Road (ERR), Northern

Ring Road (NRR) and Airport Road, each with a posted speed 120 km. These freeways are some of the

main expressways in the city, linking east to west and north to south. Pre-Cast concrete segments were

selected as the construction methodology to be applied on most of line 6 sections; specifically, Precast

Segmental Method (PSM) and Balance Cantilever Method (BCM) were applied at the viaduct links that

are crossing the NRR and ERR respectively.

Temporary Traffic Control Plans (TTCPs) were applied and operated to facilitate the construction

stages of these viaduct sections. Parts of the TTCPs require occupying 1-2 lanes temporary for a period of

5-6 hours on several nights to transport the concrete Segments. To maintain traffic safety on these main

freeways during the temporary night closures, Rolling Road Block (RRB) technique was applied to lessen

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the impacts of decreasing the operational speed (and associated shockwave) of the freeways from

120km/h to a complete stop. This technique was applied and operated successfully more than 10 times.

Acknowledgements

I would like to acknowledge ADA, DB, PMCM, Mawqif and RTP for their believing in the Rolling

Roadblock Technique and the collaborative effort during all stages of work, also the drivers for their law

respect and interacting with the changes during work nights.

References

[1] General Authority for Statistics, Saudi Arabia, https://www.stats.gov.sa/en. Accessed on: 23 Apr. 2017.

[2] Riyadh Municipality, Saudi Arabia, https://www.alriyadh.gov.sa/en. Accessed on: 23 Apr. 2017.

[3] Riyadh Metro Project Website, Saudi Arabia, http://riyadh-metro.com. Accessed on: 23 Apr. 2017.

[4] The American Traffic Safety Services Association15 Riverside Parkway, Suite 100Fredericksburg, VA

22406-1022800-272-8772, Federal Highway Administration, U.S. Department of Transportation.

[5] USE OF POLICE TRAFFIC SERVICES IN WORK ZONES, Maryland State Highway Administration

Page 1 of 17 Office of Traffic and Safety August 2005 Use of Police Traffic Services in Work Zones.