Road water detection

1. A vehicle computer comprising:

a memory; and

a processor programmed to execute instructions stored in the memory, the instructions including:

receiving a first tire pressure of a first tire at a first time;

receiving a second tire pressure of the first tire at a second time;

comparing the first tire pressure to the second tire pressure; and

determining that a road is flooded based on (a) a difference of the first tire pressure and the second tire pressure, and (b) ruling out a false positive by:

receiving a third tire pressure of a second tire;

receiving a fourth tire pressure of the second tire after receiving the third tire pressure; and

confirming that the road is flooded based on comparing (a) the difference of the first and second tire pressures of the first tire to (b) a difference of the third and fourth tire pressures of the second tire.

2. The vehicle computer of claim 1 , wherein comparing the first tire pressure to the second tire pressure includes determining a rate of change of the second tire pressure relative to the first tire pressure, comparing the rate of change to a predetermined threshold, determining that the rate of change exceeds the predetermined threshold, and determining that the road is flooded as a result of determining that the rate of change exceeds the predetermined threshold.

3. The vehicle computer of claim 1 , wherein ruling out the false positive further includes:

receiving a first exhaust gas temperature;

receiving a second exhaust gas temperature after receiving the first exhaust gas temperature;

comparing the first exhaust gas temperature to the second exhaust gas temperature; and

determining that the road is flooded based on a difference of the first exhaust gas temperature and the second exhaust gas temperature.

4. The vehicle computer of claim 1 , wherein ruling out the false positive further includes comparing images of an area around a host vehicle and determining that the road is flooded based on similarities in the images resulting from flood water hiding distinguishing road features.

5. The vehicle computer of claim 1 , the instructions further including determining a water depth.

6. The vehicle computer of claim 5 , wherein determining the water depth includes querying a remote server and determining the water depth from a response received from the remote server.

7. The vehicle computer of claim 5 , wherein determining the water depth includes estimating the water depth based at least in part on the difference of the first tire pressure and the second tire pressure.

8. The vehicle computer of claim 5 , wherein determining the water depth includes estimating the water depth based at least in part on a difference of a first exhaust gas temperature to a second exhaust gas temperature.

9. The vehicle computer of claim 1 , the instructions further including adjusting a ground clearance of a host vehicle based on determining the road is flooded.

10. The vehicle computer of claim 9 , wherein adjusting the ground clearance of the host vehicle includes commanding a suspension system controller to increase the ground clearance.

11. The vehicle computer of claim 1 , the instructions further including determining that a host vehicle is operating in an autonomous mode.

12. The vehicle computer of claim 11 , the instructions further including comparing a water depth to a predetermined threshold, determining that the water depth exceeds the predetermined threshold, and commanding an autonomous mode controller to seek a different route as a result of determining that the water depth exceeds the predetermined threshold.

13. The vehicle computer of claim 1 , the instructions further including determining that a host vehicle is operating in a non autonomous mode and commanding a user interface to present an alert representing at least one of an indication that the road is flooded, a water depth, an indication of whether the host vehicle can traverse the road, and a recommendation of a different route.

14. A method comprising:

receiving a first tire pressure of a first tire from a first tire pressure sensor at a first time;

receiving a second tire pressure of the first tire from the first tire pressure sensor at a second time;

comparing the first tire pressure to the second tire pressure; and

determining that a road is flooded based on (a) a difference of the first tire pressure and the second tire pressure, and (b) ruling out a false positive by:

receiving a third tire pressure of a second tire;

receiving a fourth tire pressure of the second tire after receiving the third tire pressure; and

confirming that the road is flooded based on comparing (a) the difference of the first and second tire pressures of the first tire to (b) a difference of the third and fourth tire pressures of the second tire.

15. The method of claim 14 , wherein comparing the first tire pressure to the second tire pressure includes determining a rate of change of the second tire pressure relative to the first tire pressure, comparing the rate of change to a predetermined threshold, determining that the rate of change exceeds the predetermined threshold, and determining that the road is flooded as a result of determining that the rate of change exceeds the predetermined threshold.

16. The method of claim 14 , further comprising:

determining a water depth,

comparing a water depth to a predetermined threshold,

determining that the water depth exceeds the predetermined threshold, and

commanding an autonomous mode controller to seek a different route as a result of determining that the water depth exceeds the predetermined threshold.

17. The method of claim 14 , further comprising:

determining that a host vehicle is operating in a non autonomous mode; and

commanding a user interface to present an alert representing at least one of an indication that the road is flooded, a water depth, an indication of whether the host vehicle can traverse the road, and a recommendation of a different route.

18. The method of claim 14 , wherein ruling out the false positive further includes:

receiving a first exhaust gas temperature;

receiving a second exhaust gas temperature after receiving the first exhaust gas temperature;

comparing the first exhaust gas temperature to the second exhaust gas temperature; and

determining that a road is flooded based on a difference of the first exhaust gas temperature and the second exhaust gas temperature.

19. The method of claim 14 , wherein ruling out the false positive further includes:

comparing images of an area around a host vehicle and determining that the road is flooded based on similarities in the images resulting from flood water hiding distinguishing road features.

20. The method of claim 14 , further comprising adjusting a ground clearance of a host vehicle based on determining the road is flooded.