The influence of four different elastomeric materials on the low temperature dynamic properties of bitumen was determined using a Rheovibron Viscoelastometer. The four elastomeric materials included two waste products and two liquid rubbers : powdered vulcanized tire reclaim rubber, precipitated waste SBR latex from an effluent recovery system, liquid carboxy-terminated butadiene-co-acrylonitrile polymer (Goodrich CTBN), and liquid polybutadiene with terminal allylic bromine substituents (Polysar Liquid RTV Polymer). The results of the evaluation indicate that liquid polybutadiene is the most efficient low temperature flexibilizer, as might be expected from its low second order transition temperature (−85°C). A comparison of the penetration of the rubber-bitumen mixtures with the Brookfield viscosity reveals that the addition of rubber markedly reduces the temperature susceptibility. Attempts were also made to follow the thickening behavior of bitumen/ CTBN rubber mixtures after the addition of calcium hydroxide. The large increase in viscosity immediately following the addition of calcium hydroxide was followed by a gradual return to a slightly lower viscosity than the original bitumen-rubber mixture. The implications of the low temperature dynamic transitions, viscosity behavior, penetration values and thickening behavior of bitumen/rubber mixtures with respect to road performance are discussed.