In order to achieve the goal of carbon neutrality and explore the impact of COVID-19 on urban road carbon emission, this study applied and improved a near real-time road carbon emission estimation method for typical Chinese urban agglomeration to improve the rapid evaluation of sustainable development. As a result, we recorded the daily road carbon emission for 12 cities in the Beijing–Tianjin–Hebei (JJJ) region under the impact of the epidemic, exploring the road carbon reduction effect caused by COVID-19. Singular value decomposition method was used to analyze the temporal and spatial characteristics of road carbon emission changes among cities and to explore the urban resilience oriented to public events. The results show: (1) In the JJJ region, the carbon reduction effect caused by COVID-19 is significant, but it lasted for a short time. In the three periods—before the epidemic, strict lockdown period, and post-lockdown period for prevention and control—the total daily road carbon emissions in the 12 cities were 170,000–190,000 tons, 90,000–110,000 tons, and 160,000–180,000 tons, respectively. (2) Cities in the JJJ region showed different road carbon reduction potential under short-term administrative control. During the “strict lockdown period” (23 January–25 February 2020), the average change rate of road carbon emissions in Beijing was −78.72%, which had great potential for reduction. However, the average change rates of Xingtai and Zhangjiakou were only −7.53% and −8.66%, respectively. (3) There are spatiotemporal differences in carbon emissions of urban roads in the JJJ region under the impact of the epidemic. During the gradual reduction of COVID-19 restrictions, great differences between cities on weekends and holidays arise, showing the road carbon emissions in Beijing on weekends and holidays are far lower than that in other cities. (4) In the face of public emergencies, the larger the city is and the more complex the function of the city is, the more difficult for the city is to maintain a steady state. This study not only provides an idea for the dynamic monitoring of urban carbon emissions to improve the rapid evaluation of urban sustainable development in post- and pre-lockdown but also fills the gap in the research on the differences in the response of cities to sudden security incidents from the perspective of road carbon emissions.