No, we don't.

Most people around here would panic if a "ghost" in a wheelchair popped out in front of them. I can see cars at full throttle crashing through buildings now!

For the speedbump? then how do you drive down the street without damage to your machine?
or maybe you meant for the handicap spot, in which case, how does the handicapped person use it?
and of course, who pays for the damage to the car? in our litigous society, it'll be the installer of the spikes / posts, meaning either the business, who will pass that cost on to you, via higher prices, or the municipality, who will also pass the cost onto you, via higher taxes

I mean think about it, we live in a society where if someone breaks into your house, and cuts himself on a knife you left laying around, he can, successfully, sue you, at least in some states
Even here in conservative Texas, folks have successfully sued cities over damage caused to their cars when they hit an uncovered hole caused by roadwork

Unless you meant an IMAGE of spikes and posts, that'd be ok, and might even work well

Gotcha, my reading comprehension is usually quite good, but sometimes I miss the obvious  

Kill the car, no power steering, not good
vacuum assisted power brakes will work for a few applications (only really need one) but if brakes are electrically assisted, nope
would also scramble Anti lock brakes / electronic stability control systems, with unpredictable results
And what happens when the system goes haywire (or is hacked) and starts EMPing drivers who were not in violation? killing a car via EMP is killing it permanently
Overall not a good Idea

It's sorta like the law requiring cars to stop when a school bus is unloading; a good idea on the face of it, but now we have taught a whole generation of kids they can just waltz obliviously out into the street regardless of traffic, and yes, the consequences of that are starting to come home, as kids are getting hurt doing this

And, if the system had a glitch and killed a car whose driver wasn't in violation?
we have 'road humps' they suck to drive over, but they slow speeders down mostly (some folks are too dumb to learn
as for the folks who take parking places meant for the disabled? the rest of us can fix this without fancy booby traps
next time you see someone parked in a handicap spot, take a pic, call the cops, and if he drives off before they get there, you have proof (be sure you get the plate)
better yet, get a valve cap that has a core remover, put it on your vehicle, and use it on these jackwagons
Four flat tires tends to get someones attention pretty quickly

What's vigilante about calling the cops? or taking a pic?
and vandal? no
the car is not in any way damaged, all he has to do is re inflate the tires

unlike the EMP idea, no one is actually hurt