Drivers are slower to perceive stop-and-go traffic than deceleration or lane changes ahead

Exploring the effects of critical driving situations on driver perception time

 

The time it took that truck to stop is about how long it took some drivers to even perceive stop-and-go traffic (in a study focused on a total of 1417 rear-end crashes and near crashes).

Anyway, if I were approaching a situation like this, I'd be slowing way down, with flashers on, until getting past the bus (as if it were a schoolbus that hadn't put out its stop sign yet). The driver's perception of moving pedestrians was fast, but the stopped bus with people exiting wasn't part of it, as far as stopping went (and the truck was travelling faster than the first vehicle that passed by the bus).

Similarly, for traffic that is stop-and-go, like a backed-up exit lane, my perception includes the potential for those slow moving vehicles to pull into my lane (which has been known to happen), so my speed will be reduced to pass by the stop-and-go traffic. Recognizing a critical driving situation in advance can make it non-critical in that case. Reducing speed gradually also helps other drivers respond faster, as the study suggests (and in my experience, nobody has had to slam on their brakes around my truck, even though we end up travelling much slower than the speed limit for a while).