Interstate

What are the railroad style barriers for used for on some interstate highways?
Q. Ever since moving to Virginia we have noticed railroad crossing style barriers at the entrances and exits for the interstate. Im not sure if any other state may use them but they seem to be a big thing in the area we moved to. What are they used for?
Asked by Roy - Sat Dec 15 23:39:57 2007 - - 3 Answers - 0 Comments

A. I am a truck driver so I know where you are talking about. They are part of an automatic fog detection system that when heavy fog forms it automaticly shuts down the interstate. also the police can manualy activate them if they need to shut down the road. Some other states use them. WI has them along I43 S of milwaukee. WY has them along I80
Answered by stephenn1998 - Sun Dec 16 00:27:17 2007

The power that the car engine makes has to overcome aerodynamic drag on the interstate in order to maintain a?
Q. constant speed. Assume the power required of a car s engine to overcome aerodynamic drag is proportional to the velocity in meters per second cubed. How much is the drag reduced if you slow from 80 miles per hour on the Interstate to 55 miles per hour? Would this save gas? If so, would it improve your fuel economy? why or why not? (100 words please) Given the cost of gas, this might be important. Also, underinflated tires waste gas.
Asked by yeahuhword - Sun Jun 8 09:39:54 2008 - - 2 Answers - 0 Comments

A. I'm not a physicist. But generally, power consumed is a cube function of speed. Meaning that if you double an object's speed (an electric motor, for example) it consumes eight times the power. This is not entirely true with automobiles, as there are waaay too many forces in play. Aerodynamic drag is also exponential: meaning that a Corvette doubling it's speed incurs less of a drag increase than a Mack truck. Then there is gearing and engine efficiency: how a car is geared and what RPM it turns at highway speed makes a huge difference (thus the debut of the CVT).
Answered by Malibu Ken - Sun Jun 8 09:51:55 2008

Is congress banned from regulating interstate commerce?
Q. Do you guys think congress should be banned from regulating interstate commerce? I think that what goes on in the states should not be controlled by congress?
Asked by ashley m - Mon Mar 3 12:38:58 2008 - - 2 Answers - 0 Comments

A. You answered your on question. What goes on within a single state can not be regulated by congress, when the enterprise goes over state lines it can be regulated. For example if a dairy farm in your state sells poisonous milk, and all his business is within your state, and your state has no laws concerning poisonous milk then he can sell all the bad milk he wants. If he tries to sell his bad milk in my state he has crossed state lines and I am protected by the food and drug administration. So I am protected against farmers selling bad food. Why don't you want to be protected???
Answered by hfrankmann - Mon Mar 3 12:48:25 2008