Taxi Driver's Bubble China is the only place I've been where the taxi drivers must sit inside a molded plastic "bubble" to protect themselves from attackers and robbers. Use of the shields became mandatory in 1988. Almost every one of Shanghai's 50,000+ taxis are equipped with the shields that fit around the driver's seat. Most are still made out of reground polycarbonate plastic which scratches easily and yellows - thus making it difficult for drivers to see clearly. A few taxis are equipped with a better, US-made plastic called copolyester. It remains clear and doesn't scratch easily. So why aren't all taxi shields made from the clear plastic? Probably for the same reason that all taxi companies in Shanghai are required by the government to buy the same model Volkswagen. It's a system ripe for corruption.