>someone tootling along at 30 odd.
>Completely oblivious to the two police cars with sirens, blue lights, & blowing horns stuck behind them.

Or not oblivious, maybe the driver thought he/she absolutely must not exceed the speed limit with two police cars behind ...

When I still lived down south, waiting at a T-junction to pull out, I observed two fire engines with flashing blue lights pull out on to the forecourt of the fire station opposite. Car from my left dutifully stopped to allow the fire engines out, car from my right, driven by an old dear, could've stopped but didn't, drove in front of the fire engines. Fire engines then pulled out behind the old dear, now with sirens going. Old dear freaked, stopped her car beside a central refuge (so the fire engines couldn't get past), tried to pull over the kerb to the left, stalled her car, restarted it, tried to pull over the kerb again, stalled it again ... all this holding up the two fire engines ... But literally some twenty yards in front of her car was an (empty) bus stop layby. Eventually, the white helmet in the front fire engine had to get out, walk to the driver's side of the old dear's car and tell the clueless old bat to drive to the bus stop ...