JINAN, China — On a smoggy afternoon, huge log carriers and oil tankers thundered down a highway and hurtled around a curve at the bottom of a hill. Only a single, unreinforced guardrail stood between the traffic and a ravine.

The route could make for tough driving under any conditions. But experts are watching it for one feature in particular: The highway curve is paved with solar panels.

“If it can pass this test, it can fit all conditions,” said Li Wu, the chairman of Shandong Pavenergy, the company that made the plastic-covered solar panels that carpet the road. If his product fares well, it could have a major impact on the renewable energy sector, and on the driving experience, too.