**2.3 System boundaries and assumptions**

The system boundaries for the baseline WRM operation scenario where the WRM agency does not use Road-Weather Information System are shown in **Figure 1**. The WRM vehicle has to pass the road section four times during a snowstorm event. The length of the road section is 10.4 km; therefore the vehicle travels 41.6 km. The WRM vehicle conducts gritting and plowing simultaneously. The salt consumption is 40% higher than in the preventive WRM operation scenario, reaching 10 tons (**Table 1**). Because of the plowing, the fuel consumption of the WRM vehicle increases to around 50 L per 100 km (**Table 1**). Other vehicles passing the road section during snowstorm event must adapt their driving to the snow conditions on the road. We assumed fuel consumption to be 10 or even 20% higher in

### **Figure 1.**

*System boundaries for the baseline WRM operation scenario.*

case of driving on a road with snow bonding compared to driving on snow-free road (**Table 1**).

The system boundaries for the preventive WRM operation scenario, where the WRM agency uses Road-Weather Information System are shown in **Figure 2**. In this scenario, the WRM vehicle drives at normal speed (30 km/h), consuming around 40 L of diesel fuel per 100 km (**Table 2**). The WRM vehicle conducts a preventive gritting before the beginning of the snowfall and two more gritting operations during the snowfall event lasting for 10 hours. The 6 tons of road salt are required for such an operation, taking into account the length of the road section (10.4 km) and the fact that the WRM vehicle passes the road section three times. No plowing is required. All other vehicles passing the road section during a snowstorm event are assumed to be able to drive at normal speed. The fuel consumption of vehicles was accounted accordingly (see **Table 2**).

The data on the number of vehicles passing the particular road section considered in this study are from the year 2020. Data were obtained from the two traffic counting points located along the road section. It was assumed that the daily traffic in the


#### **Table 1.**

*Input data for baseline WRM operation scenario without application of road-weather information system. Winter road maintenance operation and road traffic mobility during snowstorm events are adapted to conditions with snow accumulating on the road surface.*

*Pathway toward Sustainable Winter Road Maintenance (Case Study) DOI: http://dx.doi.org/10.5772/intechopen.110764*

#### **Figure 2.**

*System boundaries for the preventive WRM operation scenario.*

studied section is the average number from the two counting points. Based on these data, it was assumed that during a 10-hour weather event, the road section is passed by 1500 passenger cars, 100 light-duty trucks, and 50 heavy-duty trucks. For passenger cars, we assumed that 40% of them are diesel cars and 60% are petrol cars, which is realistic information for Slovenian conditions, to which the case study refers.

### **2.4 Life cycle inventory analysis**

GaBi professional software (version 10.6) was used to conduct a comparative LCA analysis. Data related with the use stage of vehicles, data for the production of fuels required for vehicles and data for deicer were gathered from the Professional database, which is integrated into GaBi software. Inventory data applied in two scenarios are indicated in **Table 1** (baseline WRM operation scenario without application of Road-Weather Information System) and **Table 2** (preventive WRM operation scenario with the application of Road-Weather Information System).

#### **2.5 Impact assessment**

ReCiPe 2016 version 1.1 Life Cycle Assessment Impact method was used to evaluate the environmental impacts of two scenarios. The ReCiPe method was developed in 2008 to harmonize the results of two other methods, CML 2001 (midpoint-oriented) and Eco-indicator 99 (endpoint-oriented). ReCiPe is one of the most commonly used methods for the calculation of environmental impacts [15]. The main principles of the ReCiPe 2016 method are based on the ISO 14040 and 14044 standards. The characterization factors are continuously updated according


#### **Table 2.**

*Input data for preventive WRM operation scenario: Winter road maintenance operation and road traffic mobility in case of application of road-weather information system take place on road, which is snow- and ice-free.*

to new knowledge [16, 17]. The ReCiPe 2016 method allows the calculation of impact categories according to three-time perspectives (Individualist, Hierarchist, and Egalitarian). The Hierarchist perspective, which considers the most acceptable time period, is used in this study. The LCA results at the midpoint levels are presented by 19 impact categories (**Table 3**).
