Time Constraints: The Cost of Sustainability - Sustainable Urban Logistics: Concepts, Methods and Information Systems - page 165

the access time windows are investigated. The idea is to analyze, together with
municipalities, the main urban corridors or freight, and possible deconsolidation
options on the outskirts of large cities. This deconsolidation can occur from large
trucks to smaller (electric) vehicles at specific outskirt cross-docking locations or
urban distribution centers. Also, the identification of the main logistical corridors
in cities can facilitate the movement of freight, and make distribution centers and
supermarkets more accessible and flexible in their reception of goods. This way,
companies become less dependent on access time windows.
In general, access time windows represent strong attempts to induce significant
modifications in the city logistics system and in urban traffic in general, but they
are likely to result in severe opposition from stakeholders whose interests have
been damaged. Beyond their isolated consideration, access time window regula-
tions should be well integrated with a well designed loading and unloading plan
considering aspects such as accessibility, safety (shopping) environment, noise,
and efficient use of space.
1.3 The Impacts of Access Time Windows Regulations
The introduction of access time window restrictions by local authorities responds
to sustainability criteria, seeking to eliminate congestion and pollution from the
central areas of cities during the most sensible time of the day. However, the
analyses related to the introduction of these policies have failed to take into
account an amount of relevant inputs (Seasons 2003 ). For instance, the extra costs
imposed on freight transport companies, forcing them to use an increasing number
of extra vehicles and to cover longer distances depending on the size of the
restricted area and on the duration of the time window. Research has shown that a
non-alignment and the frequent introduction of tight access time windows have a
devastating effect on the logistics operations, cost and sustainability (van Rooijen
et al. 2007 ). Indeed, the sustainability concept is usually a combination of social,
environmental and economic sustainability (Richardson 2005 ), but while the social
side of sustainability is guaranteed by these access time window policies, this is
not the case of the other two sides, at least with respect to urban freight deliveries.
Good policy practice in urban freight transport asks for a serious attention to the
logistics supply at an early stage in the planning process. In this stage of the
planning process ex-ante analyses of policy measures based on detailed cost-
benefits-analyses (van Duin et al. 2008 , 2010 ) can provide a good evaluation of the
effects. However, we need to estimate the additional costs imposed on carriers by
access time windows, so that they can be taken into account in the corresponding
cost-benefit analyses.
Several studies (Groothedde et al. 2003 ; van Rooijen et al. 2007 ; Quak 2008 )
have focused on the effects of implementing access time window regulations. All
these studies followed almost identically the methodology for cost distribution
mapping described by Groothedde et al. ( 2003 ), consisting of four steps. The first