Sounds like you're complicating things a bit.
What you're not saying here is if you want to run multiple instances of the game at the same time. What kind of PC are you using now? It had better have a LOT of horsepower. 9/10 times, the simpler solution (a second gaming PC) is the smarter answer.
Keep in mind, Windows was not designed as a 'time sharing' system - at least not in the way you're thinking.
The traffics and the road condition has probably limited you from speeding. I really doubt how many people would speed in street road...With the slow acceleration of bus, and the kick off delay between the warning phase to the execution phase, chance for the system to be activated in street road is not high.
Depending on where you're from, I guess. Here in Canada, I have roads that have a posted limit of 50kph that I can easily manage at 110kph. (Eg, the Smith-Triller Viaduct). We have highway systems here that have a posted limit of 100kph, but speeds of over 160kph are easily managed by a skilled driver. The road conditions have nothing to do with the speed, nor does the traffic.
As to how many people 'speed in street road'- the 'street racing' problem has gotten so bad that Ontario, Canada now has a law that says if you exceed the speed limit by 50kph (and are caught) then you immediately lose your license and the vehicle you are driving (even if it isn't yours) is impounded.
It many not be a problem where you are but it's a problem elsewhere
We seem to live in a world where "technology" is the solution to all of our problems. Too bad. Everyone seems to want the instant solution, and in a defeatist sort of way goes about implementing the WRONG solution to a multitude of problems.
For example: The solution here? Driver Training. Speeding doesn't kill, it's irresponsibility. it's inability. A Bad Driver decides do do 90 through a school zone and kills someone - and "speeding" is to blame? No: It's an irresponsible idiot who thinks it's appropriate to drive at excessive speed in risk-sensitive areas. It's an irresponsible idiot without the SKILLS to drive at those speeds even where the road and conditions could possibly allow it.
I have seen, daily, drivers who don't exceed the limit that are more dangerous than the fastest drivers. Distracted, disinterested, and while licensed not qualified to drive a vehicle. Is there technology to save us from THESE people? Um... yes... how about lowering the 'standards' for dangerous driving (so that that asshole that was shaving as he changed lanes into me yesterday would be properly charged with reckless) and then trhowing the book at them. If you want to throw some high tech at the problem- how implementing technology (proper black box / telemetry recorders) to support the conviction of these drivers.
It's not how fast you go, it's what you do with the fast.
Old programmers never die, they just branch to a new address.