DOT say No to Reverse Spikes to stop wrong way drivers

Q&A | DOT spikes idea | Light on Broadway 2/3/08

By Charles Brown

Seattle Times staff reporter

Q: From time to time, readers like Scott and Deirdre Zema of Seattle and Randy Davidson of Redmond have taken note of reports of drivers entering a freeway the wrong way and ending up in a head-on, often fatal, collision.

The Zemas and Davidson are on similar wavelengths. "Has anyone thought of installing the reverse spike gates in the road on freeway offramps to prevent people from entering the wrong way?" asked Davidson. "If all four tires were flattened, they wouldn't get very far."

They're even on similar wavelengths when it comes to emergency access. "If emergency-vehicle access is required on occasion to use these exit ramps for freeway access," the Zemas wrote, "couldn't they be equipped with radio-controlled disabling devices to allow entry?"

Davidson even proposes spike strips could be separated to accommodate emergency vehicles the same way some speed bumps are.

A: Interesting proposition. But state Department of Transportation traffic engineer Mark Leth says he envisions too many issues with tire-puncture devices to install them on freeway ramps. For one, those devices are typically designed for low-speed driving conditions, such as at driveways or parking-lot exits.

"Vehicles traveling at high speeds on freeway ramps over tire spikes would pose a huge risk," he said. "If the spikes were designed to let the air out of the tires slowly, the vehicles would still enter oncoming traffic. If the spikes were designed to immediately deflate the tires, the vehicle could skid, flip or roll into oncoming traffic."

In short, driving over those devices in either direction would affect drivers' ability to safely control their vehicles, he said. And there's concern whether motorcyclists could safely drive over the tire-puncture devices.

From a highway-maintenance standpoint, such devices would require high maintenance to keep them free of debris and functioning properly in all driving conditions, including ice, he said. And, yes, they would limit road crews and emergency responders' ability to access the freeway.

"Our strategy to combat wrong-way drivers includes many visual notices on each ramp to alert the driver they are entering the wrong way."

There are directional signs on streets next to ramps. There are red "Do not enter" signs on either side of ramps, along with reflective markings that appear red when approached from the wrong direction.

But it's obvious no foolproof solution has been found.

"We are currently working with the State Patrol to review a number of locations to determine if there might be additional ways to alert drivers," said Leth.



Q: Matt Gosline of Seattle wonders if the city has any plans for dedicated left-turn traffic signals at Broadway and East Olive Way on Capitol Hill when new "red-light" traffic cameras are installed. "It is virtually impossible during the evening hours to make a left-hand turn safely due to the high number of jaywalking pedestrians at that intersection," says he. A dedicated turn signal, in his opinion, would do a lot to improve safety at that intersection.

A: "There would be some benefit to providing a protected left turn [green arrow] there," said Wayne Wentz, the Seattle Transportation Department's traffic-management director. "However, there are substantial obstacles that cause us not to.

"To begin with, there is not enough space to build a left-turn pocket. As a result, we considered running the east and west traffic flow separately. While this would allow for a green arrow, it would increase delay to all users of the intersection, including pedestrians, and cause gridlock along the Broadway corridor."

Are there other alternatives? The city thought about taking away a through-lane from eastbound Olive and turning it into a left-turn pocket, but that would also increase delay since the through-traffic volumes are higher, said Wentz. Local businesses depend on street parking, so gaining roadway capacity there would be a problem.

"However, requests from the public have prompted us to re-evaluate the signal timing at this intersection," he said. "We're going to see if we can add a little more time to the east/west movement without negatively impacting traffic flow on the corridor