Final answer:
Traffic variables like vehicle numbers and emissions have been decreasing, especially during COVID-19 restrictions, though not uniformly across regions or studied systematically. Shifts to service industries, urban traffic congestion, and fuel-efficiency in cars all influence these variables.
Step-by-step explanation:
Although traffic variables such as the average number of vehicles passing and carbon emissions have been on a decline, this decrease has not been uniformly experienced across all locations or thoroughly studied on a systemic level. This was particularly highlighted during the 2020 government-imposed travel and business restrictions due to COVID-19, which led to a noticeable drop in emissions and air pollution.
For instance, in the San Francisco Bay area, traffic reduced by about 45 percent, with emissions falling by approximately a quarter. Global reductions were even more significant in some areas, with drops of up to 80 percent.
Nevertheless, shifts in workforce dynamics from active industries like agriculture and manufacturing to service industries have increased dependence on passive transportation, leading to more driving and less walking, potentially offsetting these gains. Traffic congestion in urban centers such as Delhi further exacerbates pollution levels due to slow speeds and idling vehicles.
Moreover, natural factors such as increasingly fuel-efficient cars and variations in seasonal temperatures also play a role in influencing traffic variables and emissions.