Traffic lights are used to increase throughput at junctions and/or prioritise particular traffic flows, such priority for vehicles over pedestrians was previously presented but there are subtle ways which the design of crossing lights can have enormous impacts on users.
Looking to a specific example from Melbourne here at the crossing of Alexandra Parade and Smith Street the traffic lights control a crossroads of the busy arterial with a local access road and pedestrians in all directions. The wide median of the main road provides a refuge for pedestrians crossing but the pedestrian lights are timed so that pedestrians are unable to cross the full width in a single cycle. A Throughly boring 3 minute video captures the crossing process.
The pedestrian lights remain green for just 9 seconds, only enough to cover the full 53m (174 feet) crossing length if running at 20km/h (13 mph), the 9 seconds corresponds to the expected crossing speed of just one of the roadway widths and even here at a fast walking pace the pedestrian lights have turned red before reaching the second crossing. From terminating the pedestrians crossing its a further 45 seconds later that the traffic lights change from green. From numbers based on the timing in the video delays for the different transport modes during this free flowing light traffic can be estimated as.
Delay in Seconds for:
Cars, minimum 0, average 36, maximum 108
Pedestrians, minimum 162, average 234, maximum 315
In these conditions pedestrians are not just delayed more than vehicles, they’re guaranteed to be delayed more than the worst case for vehicles and possibly take more than 5 minutes to cross the road. There are few excuses for such a restriction on the movement of pedestrians, either the timing has been set without regard for pedestrians needlessly reducing their crossing time to the minimum, or this is intentional to clear the way for turning traffic and increase vehicle throughput during peak times. Intelligent controllers and designs are able to vary their operation at different times or in response to traffic conditions, but instead this example simply meets the bare minimum provision for pedestrians and no more*.
While the infrastructure continues to prioritise private cars there is little impetus for people to choose other transport modes despite knowing that private cars are one of the least efficient transport modes and dominate the congestion on the roads. To reduce congestion and reduce travel times for everyone we need to shift away from private car use in the densely developed areas and move to the more space efficient alternatives: walking, public transport, cycling, and hire cars/taxis. But instead we see traffic lights and intersections designed to improve car throughput and reduce their delay to the cost of other modes only further entrenching the problem.
*Calculating the walk time even with the optimistic faster pedestrian speed of 1.5m/s (5.4km/h, 3.4 mph) and the widest roadway with of >16m suggest that a walk time of >10 seconds is the minimum required, so the crossing doesn’t even seem to meet the absolute minimum walk time.