Centre Right Left Turn Lanes
Centre Right Left Turn Lanes (CRTL), where vehicles make signalized right or left turn from the middle of the street, could make streets safer for people walking, cycling, rolling and driving while making transit faster and more predicable. In many cases, they could make adding transit and protected bike lanes less expensive and disruptive.
On streets where there is already a left turn lane, CRTLs would only require some paint, signage and a arrow signal to be added. If there is no left turn lane, if there are right turn lanes, the street would likely just require restriping and some signal modifications and not require expensive widening with a signalized bay for left turns being added as a bonus.
Right turning vehicles are dangerous to people walking, cycling and rolling. Banning right turns on red and signalizing right turns can reduce crashes thus improving safety and reliability. However, right turn lanes or lanes used mostly for right turns take up a significant amount of street space, at least 6m for right turn lanes in both directions, leaving less room for cycle tracks, sidewalks, transit lanes and protected intersections. They may also reduce road capacity and be expensive to build especially if land needs to be acquired.
Right turn lanes also increase the distance and time it takes for people to walk across the street. This either requires longer signal times decreasing the predicability of transit, walking, cycling and driving and or causes people who walk or roll slowly to get stuck in the street when the light turns green exposing them to being injured or killed by motor vehicles.
Right turns are problematic for buses and trams too. Whether it is a transit lane or a generally traffic lane, one turning vehicle can hold up a bus or train full of people especially at an intersection where there is a lot of people walking. This is not an efficient use of road space either.
Bus Rapid Transit (BRT) and Light Rail Transit (LRT) would also be likely easier and less costly to implement on many streets as stops can be placed on the side of the roads with the sidewalks. Often for BRT and LRT, the vehicles run in the centre of the road to avoid conflicts with right turning vehicles. This requires more space for stops and requires passengers to wait in the middle of the road exposing them to pollution and noise. Stops in the middle of the road also likely require a wider right of way than those on the side where access can be shared with the sidewalks.
While Centre Right Left Turn Lanes would take some getting used to, it is less of a change than many other measures including roundabouts; converting streets one-way streets to two-way and two-way to one-way; banning left or right turns; and added bus lanes or bike lanes. It would take some time but with proper signage and education, people would likely adapt to it quickly.
Centre Right Left Turn Lanes may not be used anywhere yet. Who will try them first?
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Images: Streetmix, Adapted from Global Street Design Guide - Global Designing Streets Initiative
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