Re: [sumo-user] How are position and velocity computed when turningleft/right at intersections?

Is there a way to get the length of the internal edges and edges in general in traci?

Von: Jakob Erdmann
Gesendet: Dienstag, 19. September 2017 23:30
An: Do Duc Le
Cc: Sumo project User discussions
Betreff: Re: [sumo-user] How are position and velocity computed when turningleft/right at intersections?

The trajectory is a piece-wise poly-line based on a cubic spline between the incoming and outgoing lanes, The number of line segments is set by the netconvert option --junctions.internal-link-detail  (default 5).

2017-09-19 17:27 GMT+02:00 Do Duc Le <doducle91@xxxxxxxxx>:

Hi Jakob,

thank you very much. Can you tell me, how/with which formula the x-y-position of each vehicle is computed (let's consider a cross intersection where straight roads from north, west, south, east meet in the middle)? For straight movement either x or y is incremented by the velocity times timestep and the other variable stays the same, but how is it actually done when the vehicle turns? Here both x and y changes.

Best regards,

Duc

On 18.09.2017 21:29, Jakob Erdmann wrote:

Hello,

by default, vehicles drive on so-called "internal edges" while passing an intersection. They follow the car follow model just as on normal edges/lanes. You can see these edges when you disable the option "draw junction shape" in the gui visualisation settings. Only if you have built your network with the option --no-internal-links will vehicles "jump" over intersections.

regards,

Jakob

2017-09-18 13:40 GMT+02:00 Do Duc Le via sumo-user <sumo-user@xxxxxxxxxxxxxxxxxxxxx>:

Hi,

as the title says I'm interested in how the position of the vehicles are computed when turning at an intersection/junction. I know SUMO follows the car following model of Krauß and the position is computed as x(t + d t) = x(t) + v(t + d t)d for straight movement , which I also confirmed by the Traci function "traci.vehicle.getDistance( )". But I can't find any information on how the position or distance of each vehicle is computed when it turns left/right into another lane/edge (consider a simple cross intersection). It seems like the vehicle disappears from the network when it reaches the junction (at least it is not on any edge) and reappears if it leaves the junction again.

Does any of you know how those functions are computed?

Best regards,

Duc

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