OSM2PO Routing - reroute when traffic jam

Question

is possible to force osm2po to reroute when traffic jam or other problem is detected on the route ? Or is it possible to tell osm2po routing to avoid some node/way even when it is best route ?

I'm not Java programmer so I prefer non Java solution

Answer 1

Both methods outlined below provide solutions from a transportation rather than a computer science based approach.

Method 1

The way this is done properly in Travel Demand Modelling (TDM) is in the Trip Assignment stage of the model.

Using the FHWA model, you can do the following:

• In your layer, create a new column for each time period you're modelling for:
  • A new field called Volume
  • A new field called Time_to_traverse
  • Create a new column for each time period you're modelling and let's call it capacity
• You either have to compute Volume of Traffic using Trip Distribution models or existing traffic feeds
• Capacity as as a start could be assumed as 1600 passenger vehicles per lane per hour.
• V/C = Volume over capacity tells you how full the highway is

Use the following equation to estimate the Time to traverse the link:

Ti = T_o [1 + 0.15*(V/C)^4]

Where:

• T_i = Balanced (iterative approach)
• T_o = free flow travel time
• V = assigned volume for that link
• C = practical capacity

Now that you have your Volume, Capacity, and Time to traverse fields for your time periods, you can set up your model to traverse using cost=time_to_traverse rather than cost=link_length. when V/C approaches one, time_to_traverse will go up and the model will reroute accordingly

Method 2:

• Create two field in your layer: Virtual_length, and virtual_factor

• If you know when volumes or traffic jams are going to occur on certain roads, assign those roads a Virtual factor and Virtual_length = Virtual_factor * real_length

• Route based on Virtual_length

Final Note:

I think this is a traffic engineering and modelling exercise more so than a programming problem