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Re: [sumo-user] About emergency braking and Traffic Lights

When using a yellow time of 3 seconds at a road speed of 50km/h, then cars may have to brake for ~3m/s^2  in some situations.
Emergency braking occurs for cars that have very low decel values (i.e. ~1.2).  Possible mitigations are:
a) define emergencyDecel as 4.5 and disable the emergency braking warning (--mergencydecel.warning-threshold 1.1)
b) let cars drive at yellow (jmDriveAfterYellowTime 3)
c) allow higher decel values
d) increase length of yellow phase


Am Sa., 7. Mai 2022 um 17:35 Uhr schrieb Jaime Moya <eljaimo@xxxxxxxxx>:

I'm getting the "Warning: Vehicle 'id_v' performs emergency braking with decel..." message. All of these messages are related to vehicles braking at traffic lights. 

Reading the documentation ( I found that "...yellow phases which are too short in relation to the vehicle speed (giving insufficient time to come to a stop). By default this causes strong braking (Warning: emergency braking) potentially followed by rear-end collisions". However, I defined a 3 seconds yellow phase, plus a 1 second red-red phase, so I think this is enough time considering a near 50 km/h edge max. speed.

What would be the best way to solve this?

What would happen if I modify the emergencyDecel parameter to 4.5 m/s2?

I attach the simulation files.

Thank you in advance

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