Modern trends in improving vehicle traffic and road safety are leaning towards the artificial generation of traffic flows and full control over them. One method is traffic aggregation by synchronizing the traffic light system along a selected street corridor. It is then possible to assume a certain preference for a chosen direction of travel, providing it with priority in terms of travel duration along streets with signalized intersections. Cross-traffic at the sequence of intersections is subordinated to the chosen direction of travel. Traffic aggregation can be constant in both directions throughout the day or variable, both during specific times of the day and by direction of travel. Traffic aggregation through traffic light synchronization for a chosen direction of travel is facilitated in cities and residential areas with one strongly determined communication corridor intersecting with other assigned routes. The rank of the road (national, voivodeship, district, municipal) and the magnitude of the Average Daily Traffic (ADT) indicator for specific vehicle categories are of significant importance here (in Poland) for choosing the privileged, aggregated direction of travel. In the case of wanting to aggregate traffic in a city through which several routes of equal rank run, the basis for choosing the privileged aggregated direction of travel is the ADT traffic load indicator. Let us take the city of Wrocław as an example.
The following roads run through Wrocław:
National:
– A-4 motorway (tangent to the southern city border): Jędrzychowice – Wrocław – Katowice,
– road no. 94 (alternative to the motorway): Legnica – Wrocław – Opole,
– road no. 5 Lubawka – Wrocław – Poznań,
– road no. 8 Kudowa Słone – Wrocław – Warszawa,
– road no. 35 Golińsk – Wałbrzych – Świdnica – Wrocław.
Voivodeship:
– 342 Wrocław – Oborniki Śląskie – Strupina,
– 347 Wrocław – Pietrzykowice – Kąty Wrocławskie,
– 362 Wrocław – Kąty Wrocławskie,
– 395 Wrocław – Strzelin – Ziębice – Chałupki,
– 455 Wrocław – Jelcz – Oława.
The most important for Wrocław are national roads 5, 8, and 94, which run directly through the city, and voivodeship roads 342, 347, 395, and 455.
From the studies conducted in 2000 [4] on ADT traffic intensity and transit directions of heavy goods vehicles through the city of Wrocław, the following picture of road load by vehicle flows emerges. [Note: the data does not concern the load on roads 5 and 94 after the construction of the south-western sections of the Inner City Bypass (the Osobowicka St. corridor from Bałtycka, Millennium Bridge, Ostatni Grosz, Gądowianka Flyover, and the section of Klecińska St. to Szwajcarska St., Hallera Ave., Wiśniowa Ave., and Armii Krajowej Ave.). The most important road junction for the city is the intersection of roads A-4, 5, 8, and 35 at the so-called Bielany junction, located at the junction of the southern city border. The main road bringing vehicles into and out of the city is Karkonoska Ave. For comparison, the transit directions of heavy goods vehicles through the city were compiled [6]. The studies conducted in 1999 and 2000 by Prof. Zipser and his team are presented in Table 1.
The analysis of traffic flows in Figure 1 and Table 1 suggests adopting the road ranking in Wrocław shown in Table 2. The course of routes in the city’s road system is of significant importance. Linking transit routes with internal traffic roads causes periodic changes in traffic intensity and the composition of vehicle categories depending on the time of day (a significant share of passenger cars during the morning and afternoon peak hours). Limited road and intersection capacity increases the susceptibility of routes to congestion. Plans for 2007 include changing the course of national road routes 5 and 94, following the planned commissioning of the south-western fragment of the inner city bypass (Table 3). Already, after the commissioning of the Millennium Bridge with the Osobowicka and Milenijna St. corridor, a significant portion of drivers use the Inner City Bypass, which is becoming the main artery for transit traffic of routes 5 and 94, as well as internal traffic. A fragment of the Inner City Bypass on the section of Hallera Ave. (intersection with Powstańców Śląskich), Klecińska, Na Ostatnim Groszu (intersection with Legnicka St.) is heavily burdened with transit. Field observations indicate that drivers continue to use the old routes of roads 5 and 94 to avoid the highly inconvenient section of Klecińska St. from Grabiszyńska St. to Szwajcarska St. This fragment of the street is a two-lane road through which over 20,000 vehicles pass daily, intersected by a level crossing with a busy railway line to Wałbrzych. In 2007, the commissioning of two two-lane road viaducts over the railway tracks on the route to Wałbrzych is planned.
The article comes from the magazine “Logistyka” 1/2007.