China 
Africa 
Explore chapters and articles related to this topic
Extensions of time/Adjustment of the completion date
Published in David Chappell, Construction Contracts, 2015
In Balfour Beatty Construction Ltd v The Mayor and Burgesses of the London Borough of Lambeth,17 reference was made to the use of programmes for estimating extensions of time. As part of its submission in adjudication, Balfour Beatty referred to the ‘most widely recognised and used’ delay analysis methods: (I) Time Impact Analysis (or ‘time slice’ or ‘snapshot’ analysis). This method is used to map out the impacts of particular delays at the point in time at which they occur, permitting the discrete effects of individual events to be determined.(II) Window analysis. For this method the programme is divided into consecutive time ‘windows’ where the delay occurring in each window is analysed and attributed to the events occurring in that window.(III) Collapsed as-built. This method is used so as to permit the effect of events to be ‘subtracted’ from the as-built programme to determine what would have occurred but for those events.(IV) Impacted plan where the original programme is taken as the basis of the delay calculation, and delay faults are added into the programme to determine when the work should have finished as a result of those delays.(V) Global assessment. This is not a proper or acceptable method to analyse delay.
Modeling vehicular and pedestrian delays at signalized midblock crosswalk under mixed traffic conditions
Published in Transportation Letters, 2023
Sandeep Manthirikul, Vijay Teja Amshala, Udit Jain
Researchers have used various methods to estimate vehicle delay. The three methods that are used most often are vehicle delay calculation from field data, second using simulation techniques and third using analytical approaches. Out of these three, the analytical approach has been found to be the most practical approach by researchers. The most frequently used analytical approach to estimate vehicle delay is the Highway Capacity Manual (HCM) method and the Webster method. The HCM method is based on the average control delay experienced by all vehicles that arrive during the analysis period. In the case of under-saturated conditions delay component d3 remains zero as there is no initial queue in such condition (HCM 2010). The Webster method was developed based on deterministic queuing theory. It calculates the average delay per vehicle during the cycle. The first two terms in the Webster’s expression are theoretical and the last term is an empirical correction factor (Webster 1958). These have been presented further in this paper in Table 7. The first term in this expression is delay due to a uniform rate of vehicle arrivals and departures. The second term is the random delay, which accounts for the effect of random arrivals. Later, Webster modified this model by eliminating the last component, i.e., empirical correction factor and replaced it by a coefficient of 0.9 to the first and second delay components. Austroads method is another widely used vehicle delay model in Australia and New Zealand for estimating vehicular delays (Abley, Smith, and Rendall 2015). This method can be used to estimate vehicular delay at signalized intersections as well as controlled midblock crosswalks.