**3.1 Uncertainty analysis**

Uncertainty refers to data on fuel consumption of passenger cars and trucks passing the road section during a snowstorm event. Literature data indicate that increases in fuel consumption in different levels of slush vary between 10 and 30% [12–14]. Indeed, the practical experiences of the authors of this study showed that fuel consumption of passenger cars driving on roads with 10 cm snow cover increases by nearly 30%. In general, it was assumed that passenger cars and trucks consume 10% more fuel when driving on a road with snow cover, compared to driving on snow-free roads. If we assume that the traffic driving on the road with snow cover consumes 20% of fuel more than in normal driving conditions (preventive WRM operation scenario), then such a baseline scenario shows even greater environmental impacts. In such a case, differences between the two scenarios are typically 20% (GWP for example) or even more for some impact categories (up to 33% in case of impact on ionizing radiation). If we assume that the road traffic in the baseline WRM operation scenario consumes even 30% of fuel more than in preventive WRM operation scenario, the differences between the two scenarios are typically 25% (in terms of GWP, abiotic depletion of fossil fuels, human toxicity, ecotoxicity indicators etc.) and maximally 34% (in terms of ionizing radiation—IR) (**Figure 6**).

However, totally opposed findings can also be found in the literature regarding the fuel consumption of vehicles traveling on the road with snow cover. Taking into account the study of Nordin and Arvidsson [18], the fuel consumption of vehicles does not increase in conditions with 1 cm of snow cover on a road. Argumentation is that demanding driving conditions related with slippery roads or reduced visibility forces drivers to reduce the speed. Lower speed of vehicles due to the presence of small amounts of snow can result even in lower fuel consumption compared to vehicles on a cleared road driving with the usual speed [18]. But this is certainly not the case when snow cover on road reaches a few centimeters [12–14].

However, opposing findings can also be found in the literature regarding the fuel consumption of vehicles traveling on the road with snow cover. Taking into account

#### **Figure 6.**

*Relative comparison of baseline WRM operation scenario versus preventive WRM operation scenario. In case of baseline WRM operation scenario, three assumptions were taken into account regarding the fuel consumption of cars and trucks passing the road covered with snow: 10, 20, or 30% increase in fuel consumption due to the presence of snow on the road. The assumption with the highest fuel consumption was set as a reference.*

the study of Nordin and Arvidsson [18], the fuel consumption of vehicles does not increase in conditions with 1 cm of snow cover on a road. Argumentation is that demanding driving conditions related with slippery road or reduced visibility force drivers to reduce the speed. Lower speed of vehicles due to the presence of small amounts of snow can result even in lower fuel consumption compared to vehicles on a cleared road driving with the usual speed [18].
