Because transit vehicles often have long wheelbases and long front and rear overhangs, sharp changes in profile or vertical curves with low K values should be avoided. Profiles across intersecting streets and more critically across railroads should be as flat as possible or have high K values to avoid any possibility of the bottom of the transit vehicle contacting the pavement.

Limiting grades for transit vehicles depend on the power source. For diesel powered vehicles short upgrades of up to 6% are acceptable and short ramps may be up to 10%. Electrically powered vehicles often have greater hill-climbing ability than diesel powered vehicles.

Transit stations and other developed stops should ideally be on profiles of 1.5% or less to allow for accessible boarding. However, retrofits on existing roadways or profiles in hilly terrain may make this requirement infeasible. In those cases, allows for exceptions.

Low points in profiles should not be designed where a transit platform or bus pullouts are planned as the presence of a platform makes an inlet impractical and creates drainage issues.

Most transit vehicles require at least 14.5-ft of vertical clearance, not just for the vehicle height but also to accommodate equipment on top of the vehicle such as air conditioners and for future resurfacing. Transit vehicles that are fed electrical power from the top may require greater clearances depending on the design of the transit vehicle and catenary electric system.

Corridors with transit vehicles should be designed assuming lower acceleration and deceleration rates than passenger vehicles. Normal acceleration should be estimated at 3 ft/s2 and normal deceleration should be estimated at 2 ft/s2. When vehicles with standing passengers use a corridor, the design should limit maximum deceleration to 8 ft/s2. This may significantly affect the yellow times for signalized intersections.

Note that while the maximum deceleration for transit vehicles is less than the 11.2ft/s2 normally assumed for stopping sight distance for passenger vehicles, the driver’s eye height of a transit vehicle is usually significantly higher than the 3.5-ft used for passenger vehicles, allowing for greater sight distance over crest vertical curves. For sag vertical curves the headlights on transit vehicles are usually mounted higher than passenger vehicles, which should provide for greater sight distance at night. Note that increased driver eye Table of Contents Instructions Reference Links Roadway Design Manual | 22-6 height/headlight height does not increase sight distance around horizontal obstructions, so transit-heavy corridors may need to be evaluated with larger sight triangles that might be normally used for passenger vehicles.

Transit stops may be located in the center of a roadway between dedicated transit lanes with left side boarding, between dedicated transit lanes and general-purpose lanes with right side boarding, or in outside general purpose or BAT lanes with right side boarding.

Outside lane transit stops, or transit lines without transit signal priority on the signalized intersections, should usually be located on the far side of a signalized intersection so that the transit vehicle can pass through the intersection on a green before needing to stop to pick up and discharge passengers. This allows for passing traffic to continue and right turns to flow.

While transit vehicle pull-outs at stops may allow through traffic to pass while the transit vehicle is stopped discharging and picking up riders, it also may make it difficult for the transit vehicle to re-join the traffic stream when traffic density is high. In these cases, it may be necessary to design the signal timing in such a way that the transit vehicle is provided sufficient gap to leave the pullout and re-enter the general-purpose lane.

Transit stop height may vary from normal curb height (usually 6-in) to level boarding (usually 15-in to 18-in) or somewhere in between with “near-level boarding”. Transit stops without level boarding may require transit vehicles to use vehicle-mounted technology to accommodate wheelchairs. A non-vehicle alternative is for the platform to have a level boarding “hump” which lines up with the front door. This requires that the transit vehicle operator stop at an exact location at the boarding platform. These humps should have slopes of 5% or less to conform to ADA requirements and may require guard rails in the back for safety.

In some cases, BRT transit stops may need to be designed adjacent to existing roadways with longitudinal grades near or exceeding the 5% ADA maximum. In these cases, while PROWAG provides an exception to ADA for running slopes, care should be taken in the design of transitions from normal curb height to the height of the transit platform. These designs should be discussed with the assigned Registered Accessibility Specialist (RAS) before plans are submitted for review to clarify PROWAG requirements. This will help avoid any post-construction misunderstanding about conformance to Texas Accessibility Standards.

Although transit planning generally prefers locating major transit stops adjacent to signalized intersections to allow signalprotected crossings, ROW and commercial driveway constraints may make this impractical. If mid-block transit stops are considered, the designer should consider including crossings protected by pedestrian hybrid beacons so that pedestrians do not need to walk all the way back to the nearest signalized intersection to cross to the other Table of Contents Instructions Reference Links 22-7 | Roadway Design Manual| 2024 side of the roadway. Specific requirements for the application of pedestrian hybrid beacons are addressed in .

Bicycle and through pedestrian traffic on sidewalks/sidepaths should ideally be routed around the back of platforms that are located on the outside lane to avoid interfering with riders waiting and boarding/deboarding. However, in cases where this is not feasible, platforms should be designed so riders may wait in areas away from through bike/ped traffic and through bike/ped traffic is advised to stop when transit vehicles are boarding/deboarding.

Profiles through transit stops should ideally be designed at no more than 1.5% to allow for wheelchairs to turn in any direction to board/deboard vehicles. However, if the transit stop is controlled by the profile of the adjacent roadway, this might not always be practical.

Transit stops should be designed on horizontal tangents of roadway to minimize the gap between the BRT vehicle and the passenger platform. Horizontally curved platforms can be difficult for BRT vehicles to correctly dock against.