But it could be a lot more complex than that, and we've done a lot of things to change infrastructure to reduce driving hazards, because while we _know_ the average driver isn't gonna change much, we might be able to change the road a lot (and we have! banked curves, divided highways, jersey barriers, etc.).
Let's start with deer!
In 2002, the Indiana Toll Road experimented with sensors to warn that deer were present.
http://articles.chicagotribune.com/2002-07-21/travel/0207210366_1_warning-system-deer-indiana-toll-road
By 2008, they were gone (and the start date on the system was apparently mis-remembered):
http://www.dispatch.com/content/stories/local/2008/11/02/deergizmos.ART_ART_11-02-08_B1_APBOSNO.html
Dealing with deer is an ongoing issue, which you can research here:
http://www.deercrash.org/
None of it is working all that great. Volvo is/was working on an IR system for cars to spot deer at night:
http://www.goauto.com.au/mellor/mellor.nsf/story2/0409F88932ADC0E7CA2578AE001FB952
A couple years ago, it was a couple years down the road:
http://www.cartalk.com/content/i-spy-volvos-animal-avoidance-system-about-two-years-down-road
In August 2014, they were still working on it, and their goals had been reduced a bit:
http://www.telematics.com/telematics-blog/horse-avoidance-tech-latest-volvo-push/
Now, it's about the very biggest animals, and about reducing speed just a bit, to reduce fatalities, rather than total avoidance.
If you've ever lived in a place like New Hampshire or Massachusetts which has a lot of deer running across roads in twilight, with woods on both side coming within yards of the roadway, you might be prepared to spend quite a lot to never, ever, ever hit a deer. But I think the technical problem is actually insanely difficult, because the real risk is when one of those suckers crossed the road _right in front of you_, giving you next to no time to stop. If they're standing in the middle of the road staring at you, not hitting them is no harder than not hitting anything else in the middle of the road.
This thing is a depressing list of roadway modifications tried with varying but generally expensive and not completely effective results:
http://wildlifecontrol.info/pubs/Documents/Deer/Deer-Vehicle_factsheet1.pdf
RFID collars on deer in a herd, fences, crosswalks for deer, lighted signs for the drivers, laser detection of deer . . It's all here!
