In this paper, the analysis of carbon footprint values for children’s footwear was conducted. This group of products is characterized by similar small mass and diversity in the used materials. The carbon footprint is an environmental indicator, which is used to measure the total sets of greenhouse gas (GHG) emissions into the atmosphere caused by a product throughout its entire lifecycle. The complexity of carbon footprint calculation methodology is caused by multistage production process. The probability of emission greenhouse gases exists at each of these stages. Moreover, a large variety of footwear materials – both synthetic and natural, give the possibility of the emission of a lot of waste, sewage and gases, which can be dangerous to the environment. The diversity of materials could be the source of problems with the description of their origins, which make carbon footprint calculations difficult, especially in cases of complex supply chains. In this paper, with use of life cycle assessment, the carbon footprint was calculated for 4 children’s footwear types (one with an open upper and three with full uppers). The life cycles of the product were divided into 8 stages: raw materials extraction (stage 1), production of input materials (stage 2), footwear components manufacture (stage 3), footwear manufacture (stage 4), primary packaging manufacture (stage 5), footwear distribution to customers (stage 6), use phase (stage 7) and product’s end of life (stage 8). On these grounds, it was possible to point out the life cycle stages, where the optimization activities can be implemented in order to reduce greenhouse gases emissions. The obtained results showed that the most intensive corrective actions should be focused on the following stages: 3 (the higher emissivity), 4 and 8.
The paper presents development of the new Polish method for performing capacity analysis of basic segments of dual carriageway roads (motorways and expressways). The method is based on field traffic surveys conducted at 30 motorway and expressway sites (class A and S roads) in Poland. Traffic flows, composition and travel times were observed in 15-min intervals at each site using ANPR filming method. These data were used to calibrate a family of traffic speed-flow relationships for different roads, based on Van Aerde model. Free flow speed of traffic and road class are the basic parameters defining the speed-flow relationship and the value of capacity per lane in pcu/h. Traffic density was adopted as the measure of effectiveness for defining the level of service. The paper describes derivation of formulae for estimation of free flow speed for different types of roads as well as determination of equivalent factors for converting vehicles to passenger car units. The method allows us to determine capacity and the level of service based on existing or forecasted traffic flow.