I might have missunderstood u the first time, u are correct in that Hesienberg should have known his speed rather than his position, if the cop meassured his speed there is no way that Heisenberg (or the cop) can know were he is with any greater accuracy.
Zimmer, Heisenberg was counting on the cop not understanding quantum physics. Otherwise he would have gotten a ticket.
The uncertainty principal can be expressed as: dx*dv>h/(4pi*m)
dx is the location and dv the velocity uncertainties, and m is the mass.
h - the Plack constant is very very small! 6.6e-34 Jouls Seconds.
m the mass for elementry particles is also very very small and the ratio h/m is not so extreme.
However, a car weights over a ton, so h/(4pi*m) is something like 10^-37.
Even if the cop could measure the speed to an unthinkable accuracy of 10^-37 meter/second he can still determine Heisenberg location to within a meter - and give him a ticket.
Just saying.