A better design would be with caterpillar tracks. I am an expert on these sorts of things, here's my credentials.
*flashes credentials*
(,
Wed 20 Oct 2010, 14:05,
archived)
*flashes credentials*
It wouldn't need to move that fast (or even at all if you could just sit at the end of a street and lure them in). You might want a turn of speed at the end of your shift if you wanted to get away though.
(,
Wed 20 Oct 2010, 14:10,
archived)