Home assignment 3: road traffic assignment and performance analysis
Giulio Piccinini Amin Acabarali
1. Characterization of the demand 2. Evaluation of network performance and identificationof the critical situations 3. Evaluation and report of the impact of interventions in the critical links and on the overall network 4. Annexes 5. References pag. 10 pag. 35 pag. 7 pag. 3 pag. 4
Characterization of the demand
The trip demand for the Oeiras interurban network, as depicted by the G2 Matrix, shows that the principal generators and attractors are related to zonecentroids which are in essence freeways and highways. Contrary to other Oeiras zonal definitions which are associated to local parishes, i.e. Buraca, Alfragide, Restelo, etc., the demand generated and attracted by these zones cannot be easily associated with land use patterns. This is mainly because of the fact that freeways and highways centroids are not true generators and attractors, due to the factthat, most likely, the real trip demand is originated from outside of interurban area which is demarked by the city of Oeiras. In this case, the city serves as a passage point to other destinations. The main trip generators for this area are the CREL highway, A5 Lisboa highway, 2ª Circular highway, IC-19 Sintra highway, A5 Cascais highway, the Amadora Centro zone and the Queijas zone, all ofwhich, individually, produce an excess of two thousand and a half trips. The main attractors are the following highways: CREL-Alverca, A5-Lisboa, 2ª Circular, IC 19-Sintra, A5Cascais, and Zona Comercial - Alto Montijo. It is worthwhile to note that, among the only three trip origins / destinations that are not related to highways - the Amadora Centro zone, the Zona Comercial – Alto Montijo zone and theQueijas zone - the first two zones have high trip volume associated with the fact that Amadora is the fourth largest city in Portugal and the Zona Comercial- Alto Montijo zone is linked to a shopping mall which, during the morning peak hour, attracts several individuals who are employed by that shopping mall. For what it concerns the Queijas zone, it is a residential area from where, during themorning peak hour, residents, mainly, leave to reach other destinations. OD Pair individual flow analysis (Fig. 1 in the Annexes) results in a similar set of conclusions obtained previously by looking at individual origins and destinations. The OD pairs with the highest flows are all characterized by a movement of over one thousand vehicles. They are as follows: from CREL – Alverca to A5 Cascais,from 2ª Circular to A5 Cascais and from A5 Cascais to A5 Lisboa. These OD pairs start and end in highways and, therefore, can be classified as passage points. There are two additional OD pairs which are associated with localities: from Alto Da Boa Viagem to Queijas, and from Queijas to Zona Comercial Alto Montijo. High flow volume from the first OD pair can be explained by a movement ofindividuals, who live in a nearby zone, to their work spots (these two zones are neighbors) to take advantage of either more affordable housing or to benefit from higher quality housing (profile of local shop
owner who use private transport to travel short distances). On the other hand, medium to 3
medium-low class individuals, who live in nearby areas and are still able to afford private cartransport, are seen as the bulk of the labor supply to shopping malls. This explains in great part the flux from Queijas to Zona Comercial Alto Montijo It is generally common to see a high degree of trip concentration in a reduced quantity of matrix cells when survey studies are made for total trips within a given area; for instance, in Lisbon, it was estimated that less than 30 percent of the OD flows...