What are the performance and environmental differences between cutback bitumen and emulsions?

Cutbacks use petroleum solvents to reduce viscosity, giving fast wetting and curing but higher VOC emissions, flammability, and regulatory burden. Emulsions use water as the carrier, reducing fumes and fire risk and enabling cold application, but they require correct breaking and curing conditions. Performance differences show up in temperature sensitivity, curing time, and aggregate compatibility. Many agencies restrict cutbacks due to VOC and safety concerns, favoring emulsions instead.