Yes, there will still need to be speed limits. But if, say, the roads are designed with a 12&#x27; lane, the people will tend to drive faster than on a 10&#x27; lane. (See <a href="http:&#x2F;&#x2F;www.citylab.com&#x2F;design&#x2F;2014&#x2F;10&#x2F;why-12-foot-traffic-lanes-are-disastrous-for-safety-and-must-be-replaced-now&#x2F;381117&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.citylab.com&#x2F;design&#x2F;2014&#x2F;10&#x2F;why-12-foot-traffic-la...</a> .)<p>I believe vcarl&#x27;s point is to design the roads for the speed limit, so the speed limit matches what people will perceive to be the right speed for the road. Don&#x27;t have speed limits which are lower than the perceived limit.<p>The clumsy way to do this is to put in traffic calming devices. Narrowing the streets is less in-your-face, and comes with other advantages, like cheaper road maintenance. Both are also ways to communicate the appropriate speed limit, in addition to a sign which says the same thing.