What's the goal of the rolling road block?

[kevin993]

We've seen this happen different times on LA freeways and had it happen again on the 105 this week - a police car or motorcyle weaves to slow down traffic behind them for a while. After a few minutes, they turn off their lights and everybody gets back to driving. There never seems to be a reason that we can see once they release the traffic that has now piled up behind them.

Anybody know why? If there was an accident ahead, I can see how they'd want to make room for emergency vehicles to get through or road construction vehicles to reposition themselves, but we never pass an accident or see construction vehicles. Maybe they're holding things up to permit a motorcade to get through? This is LA, not Washington DC, so that seems like a long shot. We've seen it often enough that there must be some logic or rationale beyond just making room for an emergency situation.

Are they just trying to artificially prevent people from going faster than they think prudent without setting up a speed trap and writing tickets?

[Paul K]

Number of reasons. Sometimes a chase may be heading for that stretch of road- or an oversize load may be negotiating an obstacle. Either way, it's a good way to buy time in case a highway needs to be closed.

[Scott Douglas]

The 405 gets a lot of these. I've been stuck behind these many times. I've also witnessed them from the other side of the freeway too. Most times they're used to allow either a car or truck that is stuck up against the center divider to be pushed to the side of the road, or taken completely off the freeway (hence you don't see anything). I've also seen them used to allow Cal Trans workers to take down the last few cones/signs/sign trailers from a construction zone that has had lanes closed off to traffic. This usually happens early in the morning (I'm on the road at 4:15AM most mornings) and it's only going to get worse with the work that is going to happen at the 405-22 interchange over the next 4 years.

[911pcars]

Sometimes they do this on the 101 Fwy heading northbound into Ventura from L.A. in order to close the gap on a group of nine 911s slightly exceeding the speed limit, and they didn't see the police air armada tracking their rate of speed from 5,000 feet. This tactic is an effective method to funnel them all onto one offramp to gift them with speeding tickets.

... as an example. Ask me how I know.

Sherwood

[vash]

they need to remove something from the freeway, like a mattress or something.

i once had to call one in, so i could get a huge crane to do a u-turn on HWY 101. it was a nailbiter.