The road ahead is blocked. There might have been an accident.

前面的路被堵住了。也许出了事故。

youdao

As the firemen set off, they know the road ahead is blocked by landslides.

NPR: Dam Scrutiny, Quake Aid Efforts Ramp Up in China

If you hear a traffic report that the road ahead is blocked, it is only useful if you haven't already passed the last place that you could divert to avoid the problem.

BBC: Your comments: Spring series 2009