The City of Surrey is looking to hire a transportation-happy shutterbug to photograph 1,104 kilometres of local roads this summer.
The snapshots — to be taken every five metres of public roadway — are just one aspect of a larger project to map the condition of the city’s streets, be they pristine, cracked, rutted or potholed.
The work is part of an ongoing, methodical attempt by the city to figure out the best time to dig-up or repair its aging roads, Scott Neuman, a manager of design and construction in the city’s engineering department, explained in an interview this week.
“What we want to do is maintain the paving for as long as we can — have that optimal life — and then repair it before it completely fails,” Neuman said.
The first step to doing that is knowing the condition of all that pavement.
Before you dust-off your DSLR camera and bid for the job, there’s a few things you’ll need to know. Most importantly, it’s a pretty technical bit of work that requires a truckload of fancy equipment.
What the successful bidder will need to complete the job is a vehicle fitted with laser scanners, a very high-resolution digital camera — about 5,400 pixels — and a force-measurement detection system. The camera is used for images of cracking, potholes and other blemishes, the laser measures how deep ruts in the road are, and the detection system feels and logs the bumps along the way.
What the bidder will need to do is drive the entirety of each of the city’s local roads — that is, not the major routes, which are done separately — two times. One pass is to be driven at the speed limit of 50 km/h, so the sensors detect what a vehicle would detect under typical driving conditions. A second pass is done at 30 km/h.
The work will take about two months to complete, Neuman said.
It’s not the first time Surrey has done this, and it’s a common practice in cities around North America, Neuman said. Surrey now gathers data on its major roads every four years and its local roads on an eight-year cycle.
Roadwork is underway near Bridgeview Drive and 128th Street in Surrey on Thursday as part of a multi-year project to replace aging roadways in the city.
After the city gets the photos and the data, staff can use it to try to co-ordinate roadwork with utility work. That way “you’re not seeing us rip-up brand new roads” to get at underground infrastructure, Neuman said.
For a sense of costs of the project, Neuman said scanning all the roads in the city — about 1,500 kilometres in total — would be a $250,000 job.
When asked whether the high-tech solution was more efficient than sending out work crews in trucks, Neuman said there is a particular benefit to digital feedback that workers can’t duplicate.
“The city crew driving down the street (is) highly subjective. Like how does this street compare to the next? As you do street after street after street you’ll tend to lose that consistency.”
The blemishes the gear will be capturing will include roughness and ruts, potholes, patches and repairs, and different types of cracks. They include alligator cracking, so-called because the bumps and troughs resemble the skin of an alligator, edge cracking, which happens on soft shoulders or where there is no curb, longitudinal cracking, which runs in the same direction as traffic and transverse cracking, which runs across the road.
Going into this year’s survey, Surrey’s roads are in pretty good shape overall, Neuman said.
Last time around, the sensors and camera found there was cracking on around six per cent of the roadway — comparable with other cities in the Lower Mainland — and average rutting of three millimetres, a relatively small amount.
In addition to this work, crews also drive around the city looking for problems with roads, sidewalks and signs, Neuman said.
The city’s request for proposals closes May 11.
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