Commercial truck drivers need greater flexibility within federal driver work and rest rules to allow them to select sleep times and duration based on individual need, according to a study released this week by the American Trucking Associations and sleep research firm Circadian International. ATA and Circadian evaluated whether features of the current hours-of-service rules are meeting their intended purpose of improving sleep, driver alertness and safety, according to eTrucker.com. Studying compliant and noncompliant driving scenarios, 11 sleep experts and 67 professional truck drivers found that allowing drivers to select sleep times and lengths to suit their individual needs maximized sleep opportunities, facilitating better alertness and safety on the nation's highways, eTrucker.com reports. ATA in large part supports the HOS rules implemented by the Federal Motor Carrier Safety Administration in 2004, but believes the rules should provide greater flexibility for both solo and team drivers who utilize sleeper berths.