This Diploma Thesis deals with the investigation of the impact of low cost traffic engineering measures (LCTEM) for the improvement of road safety in urban areas. A number of such measures was considered, such as speed jumps, woonerfs, raised intersections and other traffic calming measures, which have been implemented on one direction – one lane roads in the Municipality of Neo Psychiko in the Greater Athens Area. The “before & after” road accident analysis methodology with large control group was used. The control group chosen comprised the Municipalities of Holargos and Agia Paraskevi in the Athens Greater Area, which present similar road network and land use characteristics with the area considered. The application of the methodology has shown that the total number of accidents presented a statistically significant reduction, which can possibly be attributed to the LCTEM. This reduction concerns passenger cars, single-vehicle accidents and is possibly due to the behaviour improvement of drivers of 25 years old or more. The results of this research can be useful for the identification of appropriate low cost traffic engineering countermeasures for road safety problems in urban areas.