Transport/Traffic Impact Assessments

Peter Davidson Consultancy (PDC) is a specialist transport planning consultancy. We offer services to clients across the full spectrum of transportation planning activities.

Assessing the impact on travel caused by a new development used to be a simple case of designing access and parking arrangements relating only to the development itself. This grew in complexity to encompass wider network effects and to consider such issues as trip generation, trip distribution and the extent of redistribution of diverted traffic. Over recent years this complexity has continued to grow and the requirements now cover all modes of transport with an emphasis of switching travel away from car to other more sustainable modes of transport. Other issues such as the accessibility of services and travel planning need also to be considered.

Transport assessment analysis methods have consequently become more complicated and demanding, requiring substantial technical knowledge and understanding in order to ensure that all avenues are explored. Naturally, as the complexity of analysis increases, so does the importance of using a process which minimises the likelihood of errors.

PDC have a strong track record of undertaking this analysis across a range of developments and locations. These projects vary in size from the extension of a small hotel to the building of 20,000 new houses within a small town. Our services are specifically focussed for the requirements of the client.

Our approach to this type of work is generally focussed upon early consultation with the relevant local or national government authority. This enables us to immediately identify requirements specific to that department or site and helps to minimise the time spent performing the assessment.

To support this policy PDC uses all computer programs and databases that are recognised tools used throughout the transportation planning sector. These include ARCADY, PICADY, OSCADY, LINSIG, SATURN, TRIPS, TRICS, ERICA, PARAMICS etc.

Here are some brief details about some projects we have conducted in this area.

Holmstead Hotel – Traffic Impact Assessment

Date: 2005

Peter Davidson Consultancy were appointed to make a full assessment of the transport implications of a proposed development on the Holmstead hotel, paying particular attention to Trip Generation, capacity of the access junction off Homestead Lane, alternative modes of transport and the parking layout for proposed Leisure Facility. The project was successfully steered through the planning application process and is now being constructed.

The TRICS database was interrogated to ascertain the additional traffic generation associated with the proposed development, namely an additional 16 bedrooms (net figure) and a keep fit suite which will include a gymnasium, 15m swimming pool, sauna, solarium and associated changing facilities. The capacity of the access junction to the hotel was assessed using standard turning capacity calculations taken from the Traffic Appraisal Manual. The results showed that there was enough reserve capacity on each possible movement through the junction to accommodate the top end of the TRICS generation range. Car parking usage was also analysed using TRICS in order to build a picture of the scale and pattern of car parking usage at the expanded Homestead Hotel during days of maximum activity.

It was advised that the proprietor produce and maintain a travel plan to ensure that new traffic generated by the proposed hotel extension was minimised to provide benefits for those who travel in a sustainable manner to provide clear information to all staff and visitors detailing the various means of travelling to the hotel by non car modes and to develop sustainable transport facilities for, in particular, visitors to the Keep-fit Centre.

Blockbuster Video Road Traffic Access Arrangements

We were approached by Blockbuster Video in Gloucester to help them sort out their road traffic access arrangements. Blockbuster shared access arrangements with a MacDonald’s drive thro’ and during times of busy activity, traffic which queued to go into MacDonald’s, blocked access to Blockbuster, which caused intense disruption to Blockbuster’s business. Relations with the Highway Authority were also strained because the traffic queue for MacDonald’s tailed-back onto the contiguous road network impinging on a major local highway.

We were asked what we could do to ameliorate the situation. However, we were able to devise a road layout solution which solved all the problems. It enabled unimpeded access to Blockbuster. It got rid of the queue tail-back onto the major road from MacDonald’s and it left Mac Donald’s car park with about the same number of car park spaces. So this was a win-win-win. The new road layout was built and is successful operation.

Scottish Office Relocation Study

Date: 1994

As part of major redevelopment of the docklands area of the Leith, Edinburgh, The Scottish Office relocated from Central Edinburgh to a brand new purpose-built site at Victoria Quay in 1995. Over 2000 members of staff moved to the brand new building located some two miles north of the existing Scottish Office premises in the city centre.

Prior to the move, in 1994, Peter Davidson Consultancy (PDC) was employed to undertake a study of the likely travel pattern of the staff to the new site and make recommendations for transport provision. Every member of staff was asked to fill in a self-completion questionnaire and a sample of 10% was interviewed face-to-face in a stated preference survey.

The results of the survey, together with the outputs from the existing transportation models of Edinburgh, were used to construct a predictive model to Victoria Quay after relocation. Using the model it was possible to predict the demand for new direct route bus services to Victoria Quay, the likely demand for car parking spaces and the likely demand for cycling facilities. Recommendations were then made to The Scottish Office regarding the services and facilities required to satisfy those demands.


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