This is much safer than having a soil or gravel surface in which worms can survive. (all-about-puppies.com)
The 150 - mile Pennsylvania leg is a bucolic, car - free option for all experience levels (and all bike types), with an average 1.4 % grade and a smooth, packed gravel surface. (health.com)
In the Missouri case, which dates to 2012, the church applied for funding to replace the pea - gravel surface of its child learning center's playground with material made from recycled tires. (usatoday.com)