(June 25, 2007) -- Drivers in multiple parts of LB will soon have additional reasons to watch their speed.

In just weeks, electronic street signs are slated to begin displaying drivers' speed back to them.

The speed-feedback signs -- 34 to start (two more coming) in 24 locations (some in two directions, others in one, listed below) -- use radar to show approaching drivers' speed, a reminder to ease off on the gas pedal when called for.

LB Traffic Engineer Dave Roseman says they're currently quietly operating and recording speeds to provide a baseline comparison once the displays are turned on, anticipated in early July.

Each sign (in photo on Wardlow Rd. east of Studebaker Rd.) has a radar unit behind the sign panel, which sends out a radio wave and reads its reflected data. A small antenna lets engineers download speed data and compare it week to week to see if they have spikes at certain times, overall reductions, etc.

Traffic Engineer Roseman says early studies in other cities showed some fairly significant reductions in overall speed by simply raising drivers' consciousness as they zoom by. It's the same concept used in LB's trailer-mounted rolling-radar billboard that's been placed in various parts of town, but the new speed-feedback signs are strategically mounted near permanent speed limit signs.

No, it's not absolutely foolproof. Mr. Roseman acknowledges that when two cars approach, the lead car's speed may be read and the second one missed, but the safety message still comes through: watch your speed. The radar's range can pick up vehicles from about 400 feet away, he says says.

How were the locations chosen? Mr. Roseman said Public Works, working with LBPD, sought locations spread around the city (two more locations pending. Ultimately there'll be four in every Council district), a mix of smaller streets, higher volume routes and areas where LBPD has identified speeding issues. "We tried to approach this from multiple aspects to try and improve safety and also get better speed compliance," Mr. Roseman said.

Part of the challenge was electronic; some locations considered for the signs weren't possible due to technical issues (poor terrain, objects in the way, etc.).

And there were other technical issues to surmount, Mr. Roseman said.

The original version of the speed-feedback signs needed 110 volts AC all the time...but LB's street light system (the planned power source) isn't "on" during daylight hours. Mr. Roseman says the City worked with 3-M (the speed-feeback sign manufacturer) to develop a new type of sign that works like some battery-operated devices: when the street lights are on, the signs operate and the battery is recharged; when the street lighs are off, the signs run off the battery.

Mr. Roseman says the City hoped the signs could be solar-powered but apparently the technology hasn't quite reached that point yet...but two of the signs will be solar powered as a test.

The speed-feedback signs record the data for later analysis (to see if the signs reduce speeds) but no, they don't record vehicle license plate numbers or send out tickets...at least not yet.

[July 18 text update] The signs are funded by a grant (state taxpayer money) from CA's Office of Highway Safety. [end update]