As I gazed at the nation's largest installation of permeable pavers -- 265,000 square feet of parking lot at U.S. Cellular Field, home of the Major League Baseball Chicago White Sox -- I couldn't help but think of the streets I carefully navigated before earning my driver's license.
I was living in Galesburg, Ill., where most of the streets were once paved with bricks. I loved the sound and feel of a car's suspension as it bounced over the bricks (still do), but on a bicycle the exaggerated rumble-strip sensation is hard on arm, neck, and shoulder joints as well as the derriere. In some places the ground below the bricks had sagged, producing hills and valleys that could unseat a cyclist who was paying more attention to traffic signals than the road immediately ahead.
So as representatives of the Chicago Department of Water Management and Illinois Sports Facilities Authority extolled the virtues of their $3.5 million, environmentally friendly project, I thought, Haven't we been here before?
Well, actually, no. Though similar in shape and size to yesterday's red clay bricks, today's pavers are part of an engineered pavement system that's stronger, longer-lasting, and handles rainwater much more efficiently.
Most of the parking lot's base was made from the old pavement, which had been crushed into 3-inch-diameter aggregate and combined with limestone rock capable of retaining up to 154,583 cubic feet of stormwater (or 9.25 million 16-ounce beers). Instead of painting stripes, the Unilock Eco-Optiloc pavers are placed so that two different colors -- "granite" and "charcoal" -- designate parking spaces. This pavement system, which cost 12% to 15% less than asphalt, is expected to last 40 years.
The next step to updating yesterday's brick streets is making them strong enough to carry today's traffic, an experiment that at least one public works department is conducting.
Warrenville , Ill. , is placing brick pavers on 1 mile of road. Although they cost 15% more than asphalt, the pavers are expected to deliver better lifecycle cost because of their 50-year expected lifespan. In addition, the runoff that filters through the 20-inch gravel base will be cleaner than that coming from asphalt or concrete roads.
So, yes, Virginia, everything old becomes new again -- and better.