Crews rise before the sun

Frost patrol: Crews rise before the sun


The Journal staff

They don’t whoosh around in high-speed equipment or wear Strategic Commuter Command logos.

But when most of us are still snug and secure in our beds, they are out on winter patrols protecting us from rush-hour dangers.

These highway workers from Milwaukee, Ozaukee, Washington and Waukesha Counties help plow and spread salt when snow falls. But even when it isn’t snowing, they often are seeking something that is known by several aliases: white frost, black ice, glare ice or slippery pavement.

Their mission: detect this slick operator and shake him down with salt before he can send motorists skidding toward ditches or worse disasters on freeways, county highways and the state highways the counties maintain.

And the highway crews will likely be on the lookout for ice on the roads this week as the National Weather Service is predicting freezing rain for Wednesday and Thursday mornings.

Although air temperatures near the ground will remain below freezing Wednesday morning, a warm air mass was expected to move in from the south at higher altitudes later Tuesday, producing a 30% chance of freezing rain or drizzle Wednesday.

“Snow you can see coming down, but frost is something else,” said Lyle Falk, patrol superintendent for the Ozaukee County Highway Department. “Once you have it on your car window, you have to watch the pavement a lot closer.

“What’ll happen is, frost forms on pavement. And once the traffic hits it, it’ll turn that into ice,” he said. “To the average motorist, it just looks like wet pavement, but actually it’s real thin ice.

“You’ve got a little more grace period if it comes earlier in the morning before the rush hour,” Falk said. “But if it comes later, after the rush is on, you can have a lot of cars in the ditch before you can even get there.” Frost Can Sneak Up

Frost often sneaks onto the scene first where it’s cool to be, meteorologically speaking. On bridges, where freezing winds blow under roadways. On underpasses, or on heavily wooded rural highways, where pavement is shaded and doesn’t build up a reservoir of heat from sunlight.

“What I tell my people here is, if the sky is clear and the winds are calm, and if the dew point and the temperature are within two degrees of each other, it’s a good indication that we’ll get frost on the bridges,” said Daniel Mack, assistant highway superintendent for Milwaukee County.

County workers look for a telltale tip-off: shiny pavement. Sometimes they pump their brakes to produce a little slide when a visual inspection leaves doubt; sometimes they pull over and get out for a closer look, explained Steve Geiss, field operations manager for the Waukesha County Transportation Department.

In Waukesha County, county workers check some 90 bridge decks and dozens of on and off ramps before and during the rush hour each weekday morning, he said.

Sheriff’s deputies and other law enforcement officers also are vital information sources for all highway departments, providing road reports and accident alerts.

A more high-tech tool is a system of automatic, computer- operated sensors at several locations along freeways and some highways in the area, Mack said.

A mini-weather system at each site measures wind velocity and air temperature. Nearby, a hockey puck-sized device implanted in a traffic lane measures the road temperature, tells if moisture is present and roughly measures the percentage of salt on the road if there is moisture. Technology Or On-Site Reports

The data, transmitted via land lines, is available on computers. Mack said county and city officials still find it to be useful supplemental information, although a spokesman from the state Department of Transportation said firsthand reports from observers were more accurate.

Even counties that don’t have crews on duty throughout the night put some workers on the roads in salt trucks in the early morning so they can detect and respond to problems well before the rush-hour hits.

In addition to watching for debris or responding to accidents that have toppled traffic signs, they look for such things as frost, frozen runoff from daytime melting, freezing rain, old snow being blown in a thin coating across roadways or the first falling snow of a storm.

And when highway crews encounter this potentially dangerous enemy, their preferred weapon for attacking it is salt.

When the temperature is below 20 degrees, calcium chloride is mixed with salt to lower the melting point, Mack and others said.

Milwaukee County rarely mixes sand with salt because high-speed traffic quickly blows sand off freeways and major highways. But in counties like Waukesha County, which has more rural areas, a one-to-three mix of salt and sand is used on rural county roads that have light traffic, Geiss said.

Looking For Trouble

In Milwaukee County, a minimum of 12 trucks are out from 11 p.m. until 7:30 a.m. on weekdays on freeways and major roadways. Bridges get special attention, such as the Marquette Interchange and the High Rise Bridge in downtown Milwaukee, the bridge on I-43 near Hampton Ave., and the bridge on Brown Deer Road just west of N. 107th St.

Waukesha County highway personnel don’t work overnight unless they are called in for an accident or weather emergency. But five highway workers go on patrol in separate trucks at 5 a.m. on weekdays from November through March. In Ozaukee County, a two-person highway crew works overnight seven days a week. At 4 a.m., they go out in two trucks to check bridges and ramps. In Washington County, a highway worker is on duty from 11 p.m. until 7 a.m.

Of course, all of the salt in the northern hemisphere won’t help commuters as much as the old bromide to be alert, watch their speed and otherwise use an ounce of prevention.

Copyright 1995

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