re: make shift spike strips, Mike used a garden hose and some nails in Better Call Saul. I thought that was pretty creative.
As for roadblocks, I like the idea, but it would have to be extremely short duration. Maybe a minute or two. The theme files often mention how densely packed Red is. Now I just started playing here, so I don't know how rare vehicles are on Red. But even if only one out of a thousand people has a vehicle, that is still A LOT of traffic. As someone else mentioned, at least a few of those NPCs are going to get irked enough to ram the roadblock.
I imagine that the roadblock would have to work almost like a pursuit move. Two vehicles are racing down the street, and one pulls far enough ahead to block the other vehicle and prevent it from making further progress into the next "room" on the grid. Otherwise, by the time the intended target shows up, there would ICly be a bunch of NPC vehicles stuck at the roadblock and the target could just flip a quick U-turn and head in the other direction, or otherwise 'avoid' the roadblock.