Central Loop East-West BRT corridor in Chicago, Illinois

University of Michigan, “Spring break externship connections” program AECOM, Chicago

CENTRAL LOOP, EAST-WEST BRT CORRIDOR, CHICAGO, IL Physical design enhancement alternatives for BRT Infrastructure

Cesar E. Simborth Urban Design and Transportation architect

March, 2013 *Work document only for internal use

Introduction First I would like to extend an enormous thanks to the firm AECOM Chicago, who accepted to host me during the week of March 4-8th as part of the program called: “Spring break externship connections” sponsored by the University of Michigan.

The following document is the result of the week’s work, in which I could get to know different projects the company is working on such as the “Central loop (East-West) BRT corridot”, the “Circle Interchange” and Railway expansions. Although most of the time was invested in the first project .

About the Central loop BRT, it is an small scale corridor meant to connect the Ogilvie Transportation Center, Union Station and Michigan Avenue. The project was under the “conceptual design” phase and the first geometric layouts were being worked out. About it and as part of my activities I was asked to analyze the first schemes and provide some feedback to the specialist in charge, regarding the distribution of bus ways, cycle paths and turning lanes in ways that may help minimize the buses winding maneuvers along the way.

Additionally I was asked to provide alternatives regarding the following physical components, which will start be part of further design decisions as the projects keeps moving: -Bus ways delimitation: Physical separators alternatives.

-Bus ways image: Alternatives for colored or textured bus ways.

-BRT stations and busways general layout.

The following document concentrates on providing a brief visual toolkit of alternatives for the aforementioned. Alternatives are accompanied by a “practice case” and a quick evaluation that can help inform the project and the design decision making process.

Infrastructure design alternatives Bus ways are one of the most important infrastructural components in a BRT system. They help significantly improve the performance and reliability of its operation.

Additionally, it has been learned from the Latin American experience, that aesthetic efforts pay back well in the future acceptance of this type of systems and natural increase in the number of bus users (shift in modal preferences).

1.Physical separation Physical separation is an alternative to improve the performance of a bus way in cities where rules are not easily enforced by the use of signalization, human control and/ or technological features (video surveillance systems). Based on the design chosen some of the benefits that could be attained are:

2. Busway coloration The coloration of bus ways is a possibility to be considered in order to improve the functionality of a BRT busway in two regards: a) Road safety. Having a clearly distinctive space for the exclusive circulation of high capacity buses help other street users easily recognize it and be aware of potential dangers implied by the circulation of large buses in the city.. b) Urban image. pavement coloration and texturization also helps break the neutral “gray” image of urban streets, contributing to a visually friendlier urban environment.

About this respect the following design alternatives are provided: a. Concrete pavers.

a) Flexibility: There is a variety of design alternatives which allow different degrees of flexibility, in case an broken down or in need of repair bus needs to exit the exclusive system. .

b. Contained colored concrete pavers. c, d. Colored/Printed reinforced concrete slabs.

b) Economy: Physical barriers offer a very economical cost effective bus way enforcement mechanism in the long term since they generally require -depending on its materiality- little maintenance. Reducing also the need of human control (field inspectors, transit police or alike) and expensive surveillance systems which also require specialized workforce.

Throughout the present document the following “Physical separators” design alternatives are provided, accompanied by existent practice cases and a brief assessment. a. Square b. Triangular symmetric c. Triangular asymmetric d. Triangular filleted e. Cuadrangular one side sloped f. Dotted

3.Stations/ Busways layout Considering a tentative space of 10’ wide provided by AECOM’s first layouts, an schematic layout for the internal distribution and design of the station will be provided.

Likewise it is advisable that provisions for the accommodation of the following stations program be considered in the project: -Bus leveled platforms. For waiting , boarding and alighting bus-leveled platform.

-Access. Ramps are primarily desired although stairs or service lifts could also be considered depending on local constituencies.

-Validation areas. It is desirable that the system considers off board payment.

-Card recharge and vending areas. It is desirable to count on automatized vending since it decreases the costs of “fare collection operators”.

Regarding the design of the busways, and as part of a city’s policy, it should favor the adequate operation of the BRT over private modes of mobility.

1.Bus way segregation / a. Square Already in place in: -Transmilenio system (Bogota) -Metropolitano system (Lima -Trole, Metrobus Q (Quito) Material: -Concrete

(-) -Dirt accumulation -Higher costs in maintenance -Too rigid performance in case of emergencies

(+) Top view

Section

Function

Assessment

-Economical to implement

1.Bus way segregation / b. Triangular symetric Utilization: -Transmilenio system (Bogota) Material: -Metal (Concrete)

(-) -Sharp edge damaging to vehicles

(+)

Top view

Section

Function

Assessment

-Offers an intermediate degree of flexibility.

-Easier to clean -It can use the street’s drainage system.

1.Bus way segregation / c. Triangular asymetric Utilization: -Megabus system (Pereira, Colombia) Material: -Metal (Concrete)

(-) -Sharp edge damaging to vehicles

(+)

Top view

Section

Function

Assessment

-Improved flexibility to buses over cars.

-Easier to clean -It can use the street’s drainage system.

1.Bus way segregation / d. Triangular filleted Utilization: -Metrobus system (Mexico D.F.) Material: -Metal (Rubber, Concrete)

(-) -Sharp edge damaging to vehicles

Top view

Section

Function

Assessment

(+) -Filleted edges friendlier to buses and flexibility.

-High enough to discourage mixed traffic to get in.

-Easier to clean -It can use the street’s drainage system.

1.Bus way segregation / e. Cuadrangular one side sloped Utilization: -Transoeste system (Rio de Janeiro) Material: -Concrete (Metal or Rubber)

(-) -Edges may easily deteriorate due to impacts.

(+)

Top view

Section

Function

Assessment

-Economical to implement -Flat edge friendlier to buses.

-Prioritize flexibility to buses over cars.

-Easier to clean -It can use the street’s drainage system.

1.Bus way segregation / f. Dotted Utilization: -Optibus system (Leon, Mexico) Material: -Metal

(-) -Too much flexibility, easier to invade by cars.

(+)

Top view

Section

Function

Assessment

-Softened edges friendlier to wheels -Easier to clean -It can use the street’s drainage system.

2. Bus way coloration / a) Pavers

Utilization: -Transmilenio system, Bogota, Colored concrete paver

Granular compacted base

(-) -Depending on soil conditions, pavers themselves may not offer the stability and adequate resistance for a frequent operation.

(+) Asphalt

Asphalt -Can provide color and texture in a variety of fashions.

BRT Bus way speculation in Madison street

2. Bus way coloration / b) Contained concrete pavers

Utilization: -Arequipa bus system, Arequipa (Historic center), Peru

*The exact thickness of the pavers and concrete slab will depend on the geotechnic studies, frequency of buses and soil composition)

Granular compacted base

Colored concrete paver

Steel reinforced slab

Gross sand shed

(-) -Increased budget (100%)

(+) -Can provide color and texture in a variety of fashions.

Asphalt

Asphalt

BRT Bus way speculation in Madison street

-Can offer the resistance required for a long term continuous BRT busway operation

2. Bus way coloration / c. and d. Concrete slabs Utilization: -Cartagena, Colombia

*The exact thickness of the concrete slab will depend on the geotechnic studies, frequency of buses and soil composition)

(-) -Increased budget (+25%)

(+) -Can provide color and a soft texture in a variety of fashions.

-Can offer the resistance required for a long term continuous BRT busway operation Granular compacted base

c. Colored reinforced concrete slab

c.

Steel fiber reinforced concrete Asphalt

(Reinforced concrete

Printed patterns

d. d. Printed reinforced concrete slab

BRT Bus way speculation in Madison street

Asphalt

3. BRT stations, Layout Baseline information

Considerations

- 6 bus routes already operating that will use the proposed BRT infrastructure (14, 20, 56, 60, 124, 157).

- If possible it is advisable to build a micro simulation model of the future scenario in order to predict the performance of the six bus routes throughout the BRT line and precise the number of platforms in every station.

-According to the city’s baseline information* currently the CTA busses on the BRT route have headways of 20, 15 , 7.5 and 5 minutes and combined may have a headway of around 2 minutes.

- Centralized control.

-Given the amount of routes and frequencies it would seem on a rough estimate that at least a bus waiting space should be provided prior the station and possibly some of them may have to consider more than one platform.

-Thorough operational coordination will be required.

Vending space + Fare validation

Waiting space

Docking space

Platform space

Access (Preferably ramps)

Access (Preferably ramps)

Schematic BRT Platform location in Washington Street Type 1: Single waiting space + 1 platform

3. BRT busways Layout Baseline information

Considerations

- a) The first geometrical scheme was drawn based on the first busways layouts printings provided by AECOM during the week. As it can be seen there is a wavy pattern in the the busways along Madison St. due to the identified need of providing additional turning lanes for the private modes of transportation.

-b) The second drawing shows an alternative to the current designs in which the busways geometry are maintained straight along the route.

Given the following considerations: - A BRT is a high performance bus system. In that regard the operation of the bus should be prioritized over private modes of mobility. Frequent wavy patterns for both the bus system and the mixed traffic together with high frequencies and high volumes of traffic and pedestrian circulation may lead to confusion and accidents.

-The private modes of mobility will always have free-choice alternative routes whereas the BRT doesn’t.

Sidewalk Cyclepath Station

a)

Busway Mixed traffic lanes

Current busways pattern

Sidewalk Cyclepath Station

b)

Busway Mixed traffic lanes

Optimized busways pattern

Schematic BRT busways geometry in Madison Street

Conclusions ;Physical separators -About the need of enforce the exclusivity of Bus ways, the possibility of providing physical segregation may result very effective and provide savings for the city in the long term since they don’t require “human operation and control” or specialized maintenance in contrast to more technological means (passive enforcement).

-In that regard there are many proven alternatives which may me considered for that. Being possibly more advisable for the city of Chicago, the ones that provide a degree of flexibility for the bus, given the local considerations -Limited right of way, small scale of the East-West central BRT system).

Image of the busways -Producing a differentiated design for the bus ways in contrast to mixed traffic is definitely a right assumption. It help create a distinctive image to the new system, but maybe most importantly is the fact that it helps avoid street casualties since it is much easier for other street users to identify the “high capacity buses domain”.

-The choice of the right design alternative for the busways will basically depend on the soil conditions along the route, the city’s budget and projects ambitions. For which all those aspects should be carefully assessed before making a decision.

Stations / Busways -It is advisable that in order to precise the layout scheme and detail dimensions for the stations the loads of passengers per station (boarding and alighting) during the peak hours (morning, night) are assessed.

-It is advisable to build a micro simulation model of the operational conditions of the system in order to dimension suitably the stations.

-Regarding the layout of busways it is important that the designs prioritize the operation of the BRT over the privatized modes of mobility. If car traffic is heavy in certain intersections, it is advisable that to study the possibility of alternate routes.

*Work document only for internal use