Originally posted by bloom25:
There is no way that a company can fine you based on GPS evidence. (I'm an electrical engineer, I do know what I'm talking about here. ) I wonder if they (rental companies) realize that the Department of Defense adds a random error to the GPS used by the general public.
That practice was discontinued for quite a while. GPS now is accurate to single digits in horisontal plane.
Besides, you do not know over which distance they average your speed. If it's 20 miles, then what do a few feet matter.
GPS accuracy is also effected by the number of satelites the receiver is tracking at the time. (3 needed for postion, 4 needed for altitude and postition.) Accuracy generally improves as the number of satelites being tracked increases. Cheap handheld GPS unist now are all 12-channel. Enough for you, Mr. Electrical Engineer?
As for wear on the car, that is is double sided sword. Why does it have to be only about wear? Most likely they were able to negotiate a much better insurance rates because of that equipment.
today's cars are geared to run most efficiently around 65 - 70 MPH. (My car does not even shift into overdrive until you get to 50 MPH. ) This means that wear on the engine is less at 65 Mph than at 55. Of course not. The fuel efficiency may be less because the fuel burns more or less quickly then optimal. But you can be sure that air resistance increase proportional to the square of the speed amply comensates for any increase of fuel burning efficiensy.
That is no concern of the company anyway - you buy fuel out your own pocket.
The engine wear is determined by forces on the engine which inclrease with speed.
If I were in this rental car, I know what I would do - I'd put aluminum foil over the GPS receiver's antenna. Would probably violate the contract and cost you $1500
miko
[ 06-22-2001: Message edited by: miko2d ]