> Is there a difference between secure gap, brake gap and stopping distance (from kinematics)?
- brakeGap: for a given speed, the distance until stopping when braking with constant deceleration 'decel' - stopping distance: same as above for Krauss. Some cfModels take longer to stop since they do not brake with constant deceleration. - secure gap: the distance that allows safe braking if the leader vehicle suddenly starts to brake. Roughly speaking, the following holds: egoSpeed * tau + egoBrakeGap = secureGap + leaderBrakeGap. Depends strongly on leaderSpeed For details on the code, see MSCFModel.h and .cpp SecureGap has no meaning if there is no leader vehicle Decel is the preferred/comfortable maximum deceleration used in motion planning. emergencyDecel is the upper limit on deceleration in emergency situations regards, Jakob Am Fr., 8. Apr. 2022 um 15:45 Uhr schrieb Hriday Sanghvi via sumo-user < [email protected]>: > Hello, > > Is there a difference between secure gap, brake gap and stopping distance > (from kinematics)? > > As far as I understand, the secure gap / brake gap / stopping distance > calculation does not depend on the CF model, since this calculation is the > same for all CF models. My CF model is Krauss. > > 1. My assumption was that the secure gap and brake gap are the same. But > when I check on "show brake gap" in the SUMO-GUI, and display the > "secureGap" using *traci.getSecureGap(self, vehID, speed, leaderSpeed, > leaderMaxDecel, leaderID=''), *the values do not seem to reflect what > happens in the GUI - for example, when TraCI outputs a secureGap of 0.0 - > there is still a line sized bigger than 0.0 shown in the GUI. > - What would I set as the leader speed if there is no leader in front of > it - the max speed on the lane (13.89 m/s)? > > 2. If I assume that the secure gap and brake gap are the same as the > stopping distance used in kinematic physics, then does it just use those > equations to calculate this stopping distance value? That is, using *(Final > velocity)^2 - (Initial velocity)^2 = 2 * acceleration * Distance* to > calculate the Distance for a constant acceleration / deceleration? > > 3. On a side note, what is the significance of emergencyDecel variable > used in SUMO - to put it differently, why is just one deceleration > capability value not enough? - since I couldn't find an equivalent to that > in real-world driving. > > Thank you. > > Sincerely, > Hriday > _______________________________________________ > sumo-user mailing list > [email protected] > To unsubscribe from this list, visit > https://www.eclipse.org/mailman/listinfo/sumo-user >
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