Vehicle road friction control
A road friction is determined for a road location based on a traffic speed determined from respective speeds of each of a plurality of vehicles. A vehicle can be operated based on the determined road friction.
1. A method, comprising:
determining a road friction for a road location based on a traffic speed determined from respective speeds of each of a plurality of vehicles;
determining whether the traffic speed is below a threshold traffic speed, and determining the road friction based on the traffic speed only upon determining that the traffic speed is below the threshold traffic speed; and
operating a vehicle based on the road friction.
2. The method of claim 1 , wherein the road friction is determined based on, in addition to the traffic speed, a second datum that is one of whether the location includes a bridge or overpass, a status of daylight, a rain condition, a snow condition, a fog condition, a construction condition, a presence or absence of an emergency vehicle, a presence or absence of debris, or an ambient temperature.
3. The method of claim 2 , further comprising obtaining the second datum from a map.
4. The method of claim 2 , further comprising providing the traffic speed and the second datum for an area that includes the road location, whereby the road friction is provided for the area; wherein the area is defined according to a starting point and an ending point of a segment of a road.
5. The method of claim 1 , wherein the area is included on a planned route for the vehicle.
6. The method of claim 1 , wherein operating the vehicle based on the road friction includes controlling traction, speed, steering, braking, lane keeping, or lane changing.
7. The method of claim 1 , wherein determining the road friction includes obtaining the road friction as output from a machine learning program.
8. The method of claim 7 , wherein the machine learning program is provided in an infrastructure node computer.
9. The method of claim 7 , wherein the machine learning program is provided in a computer in the vehicle.
10. A computer comprising a processor and a memory, the memory storing instructions executable by the processor such that the computer is programmed to:
determine a road friction for a road location based on a traffic speed determined from respective speeds of each of a plurality of vehicles;
determine whether the traffic speed is below a threshold traffic speed, and determine the road friction based on the traffic speed only upon determining that the traffic speed is below the threshold traffic speed; and
operate a vehicle based on the road friction.
11. The computer of claim 10 , further programmed to determine the road friction based on, in addition to the traffic speed, a second datum that is one of whether the location includes a bridge or overpass, a status of daylight, a rain condition, a snow condition, a fog condition, a construction condition, a presence or absence of an emergency vehicle, a presence or absence of debris, or an ambient temperature.
12. The computer of claim 11 , further programmed to obtain the second datum from a map.
13. The computer of claim 11 , further programmed to provide the traffic speed and the second data for an area that includes the road location, whereby the road friction is provided for the area; wherein the area is defined according to a starting point and an ending point of a segment of a road.
14. The computer of claim 10 , wherein the area is included on a planned route for the vehicle.
15. The computer of claim 10 , wherein operating the vehicle based on the road friction includes controlling traction, speed, steering, braking, lane keeping, or lane changing.
16. The computer of claim 10 , wherein determining the road friction includes obtaining the road friction as output from a machine learning program.
17. The computer of claim 16 , wherein the machine learning program is provided in an infrastructure node computer.
18. The computer of claim 16 , further comprising programming to execute the machine learning program.
19. A computer comprising a processor and a memory, the memory storing instructions executable by the processor such that the computer is programmed to:
determine whether the traffic speed is below a threshold traffic speed, the traffic speed being determined from respective speeds of each of a plurality of vehicles;
upon determining the traffic speed is below the threshold traffic speed, determine a second datum that is one of whether the location includes a bridge or overpass, a status of daylight, a rain condition, a snow condition, a fog condition, a construction condition, a presence or absence of an emergency vehicle, a presence or absence of debris, or an ambient temperature;
determine the road friction based on the second datum; and
operate a vehicle based on the road friction.
20. The computer of claim 19 , further programmed to determine the road friction based on, in addition to the second datum, the traffic speed.