In this particular field study, the authors have demonstrated that telematics can be used to monitor and improve safe and fuel-efficient driving behavior.Telematics was used to monitor various driver performance parameters: unsafe events (sudden accelerations and hard braking expressed as Yellow and Red events, depending on severity), speeding, engine revolutions per minute (RPM), and fuel economy (miles per gallon). The drivers consisted of two groups: drivers of day cabs and drivers of sleeper cabs. The drivers of both groups were monitored during a baseline period during which no feedback, coaching, or rewards were provided. Then, the drivers of both groups were monitored during an intervention period, during which drivers were provided with feedback, coaching, and rewards. As the result of monitoring unsafe events and of driver intervention, drivers of sleeper cabs showed a 55 percent reduction from the baseline in less severe (Yellow) unsafe events and a 60 percent reduction from the baseline in more severe (Red) unsafe events. Also, after the intervention process: (1) drivers of sleeper cabs showed a 42 percent decrease in percent of miles speeding greater than 65 mph, and drivers of day cabs showed a 32 percent decrease in percent of miles speeding greater than 65 mph. (2) Drivers of sleeper cabs showed a 48 percent decline in percent of miles at RPM greater than 1500. (3) At the same time that all of the above trends were taking place, fuel economy improved by 5.4 percent for drivers of sleeper cabs and by 9.3 percent for drivers of day cabs.The collected data appear to suggest that fuel economy is correlated with safe driving. Because safe driving can be said to conserve fuel and conserving fuel reduces emissions, safe driving can also be said to reduce emissions.