[criley2]

>But what about their propensity to drive really slow?

You mean like a bicycle, moped, a new parent driving extra slow, an elderly driver, or any other street legal slow vehicle does?

I understand that drivers assume the speed LIMIT is a speed suggestion, and experience road rage when driving under the limit, but there is nothing -- nothing -- illegal or unsafe about staying under the speed limit.

If there is something unsafe about it, there should be a minimum posted speed (many places have this).

[CraigJPerry]

I've seen the result of a driver unexpectedly doing just over 35mph on a moderately busy 70mph motorway. Not nice. I don't even think 35mph is that much slower really - trucks are at 56mph and they get along fine but 35ish resulted in all sorts of crazy last minute swerves.

It's generally wise not to do anything other drivers will find surprising and I guess 35mph on a motorway falls in that category.

[monocasa]

Around here, roads that have a maximum speed that fast generally have a minimum speed in the 45MPH range too.

[odonnellryan]

It's definitely unsafe if you're traveling much under the speed limit on a major highway.

Most important thing when driving is to be predictable. It's predictable to be traveling plus or minus 10 mph from what is posted.

It isn't predicted to be traveling 30mph+ below the speed limit.

(no comment on being high, just saying, it's super dangerous to be doing 30-40 on a 65mph road).

[throwaway2016a]

At least in the US you can get a ticket for going under the speed limit if it is deemed to be impeding traffic even if there is no posted minimum limit. Especially if it is a multi-lane road and you are not in the rightmost lane.

[criley2]

>At least in the US you can get a ticket

As a US citizen I will tell you this is false. We have basically no national traffic laws.

Your local state, city or other local government may have passed a law like this.

For example, in my area, it was made illegal to stay in the left lane moving more slowly than those behind you -- you must yield to the right if they want to go more quickly.

But some 99% of Americans do not live under this local law I'm discussing.

[ElijahLynn]

There are some highways that have a "minimum speed limit" sign posted. Not often, but they do exist, and you can get a ticket on those highways.

Also, a Google Self-driving car got pulled over the other day for simply going the speed limit, it did not get a ticket but I thought I would mention it.

[bryanlarsen]

You're right, it's not national. But as far as I'm aware, all states have general rules against impeding traffic. Many don't have explicit laws against moving too slow in the left lane, but the general law can and will be used against you for egregious violations.

[singlow]

Texas has a rule that you may not impede traffic by going below the limit.

http://codes.findlaw.com/tx/transportation-code/transp-sect-...

[criley2]

>except when reduced speed is necessary for safe operation or in compliance with law - See more at: http://codes.findlaw.com/tx/transportation-code/transp-sect-...

Trivial to argue that reduced speed is required for safe operation in this case, the research in this very article may be useful in that defense