As noted earlier by Sims et al. (2014), GHG emissions from transport could increase at a faster rate than for any other energy end-use sector through 2050. Thus, substantial policy intervention will be required if these emissions are to be sufficiently mitigated.
In the USA and other countries, various policy options could be adopted at the regional, state, or local level to reduce GHG emissions from transport. Examples include incentives for purchase or operation of clean vehicles, public transit, and increase in cycling and walking, as well as efficient land-use policies. Transportation pricing policies, such as a carbon fee or mileage-based user fees, could help incentivize alternative choices with lower GHG emissions (Pacyniak et ah. 2015).
Deep reductions in GHG emissions from transportation will require substantial changes to energy supply, technology, and transportation activity. Reductions in emissions from new vehicle technology are hampered by the slow rate of fleet tum-over for many transportation modes. Policy options, such as fuel taxes, vehicle efficiency standards, low carbon fuel standards, laud use controls, travel demand measures and investments in new infrastructure, are among those that may be effective in achieving reduced GHG emissions, but that are also unlikely to be quickly adopted or adopted at all without significant acceptance by key stakeholders and decision makers. The co-benefits of various strategies, such as increasing energy security or reducing congestion, may be equally or more attractive to some stakeholders than GHG emissions reductions. The development and design of policy options should be informed by policyrelevant research (TRB, 2011).
An example of a policy option that appears to have broad support in many countries is standards for on road vehicles for fuel economy. GHG emissions, or both. Such standards are in place in countries that represent 80% of new vehicle sales. These standards typically focus on light duty passenger vehicles but standards are also emerging for light commercial vehicles and heavy-duty vehicles. Problems uncovered, especially in Europe, regarding gaps between official rated values and real-world CO, emissions are being addressed, at least partially, via improved measurement and enforcement procedures. Stringent fuel economy or GHG emissions standards are shown to drive innovation, leading to the adoption of more efficient vehicle technologies (Yang and Bandivadekar, 2017).
In general, in the absence of prioritization of effective and multipronged policies that address fuels, vehicle technology, efficient vehicle operation, mode shifts, infrastructure, and travel demand, GHG emissions fr om transport are likely to increase.
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