Okay, we all hate bad drivers. Driver inter-rating systems are cool, but they are suseptable to abuse and the design of the input/output is non-trivial (e.g., Who really wants a counter on top of their car? What about convertables?)
The solution to is to make the rating system completely automatic
and relatively invisible. I would do this by installing cellular automaton devices (little computers that can sense when similar devices are nearby) in every car that follows the following simple rules:
SPEEDINGCOUNTER=0
SUNDAYDRIVINGCOUNTER=0
If passing another car: SPEEDINGCOUNTER=
SPEEDINGCOUTNER+1
If being passed by another car:
SUNDAYDRIVINGCOUNTER=
SUNDAYDRIVINGCOUNTER+1
If you consistently drive faster than the normal rate of speed, your SPEEDCOUNTER/SUNDAYDRIVERCOUNTER will approach infinity. If you drive slower than the normal rate of traffic, the inverse will increase.
Normal, everyday drivers like you and me will have ratios that are roughly equal to 1.
Drivers who intentionally try to balance their counter ratio will have a higher counter TOTAL/miles driven ratio than cool drivers.
Running totals and ratios would indicate whether or not someone is an idiot driver. Could be queried once a year upon normal vehicle inspections, or possibly scannable by roadside monitors.