How do engineers expand roads to create new lanes without moving the houses/businesses that already exist along the side of the road?

Question

For example, how do engineers create 6+ lanes where there were only 4 before? How are they able to create additional lanes when there are solid structures that exist close to where the old lanes were?

In: Engineering

Answer 1

Unless they’re going to buy up the surrounding land and bulldoze it. All they can do is just try to squeeze in more lanes where they have space

Extra space can come from removing parking spots along the road, or shrinking the sidewalks. Or removing things like bike lanes.

But really if they aren’t really making any physical changes to the road, they’re just shrinking the actual width of each lane. For example a 60 ft wide road might have 4 15ft lanes. If they wanted they could squeeze that to 5 12ft lanes. (12 ft is the typical width of highway lanes). In some extreme cases like dense urban areas lanes can get shrunk even further to 10ft, possibly under special circumstances (with city council aprroval) to even smaller, but that generally comes with rules like banning buses/trucks from using that road.