Using the international vehicle emission (IVE) model and on-road vehicle monitoring data, the carbon emission factors of three main types of vehicles in Shenzhen were calculated. Then, the authors estimated carbon emission intensities of several main roads and analyzed the spatial-temporal characteristics of transportation carbon emissions in Shenzhen. Finally, scenario analysis was used to quantitatively compare three kinds of low-carbon transport development strategies. The results showed that the transportation carbon emissions of the investigated roads were highly spatially heterogeneous, and the intensities of transportation carbon emissions in urban centers and the roads linking urban centers were higher than other roads. The transportation carbon emissions of the investigated roads had apparent daily cycle, and they had four main types: single-peak curve, double-peak curve, fluctuation curve, and stable curve. The transportation carbon emissions were high in morning and evening commuting hours during workdays. The comparative analyses of three low-carbon transportation development scenarios indicated that the mild-constraint carbon mitigation scenario could better meet the targets of socioeconomic development and transportation development of Shenzhen.