The Automatic Count Sites (Atcs) Shown Are Sites Where Traffic Flow Is Measured Allowing

APPENDIX B

The Automatic Count Sites (ATCs) shown are sites where traffic flow is measured allowing monitoring of the levels of traffic on the county's roads.

The Sites shown on the maps are each noted with their reference number. Traffic flow data is available in the form of Annual Average Weekday Flow (AAWD) for the calendar year 2006. This represents an estimate of the average number of vehicles passing that point, in both directions, on a weekday between the hours of 0600 and 2200. This isthe County Councils measure of the traffic flow on a particular link.

Each AAWD represents the collation of a large amount of data. In depth analysis and breakdowns of data by time, date and direction are available.

The Congestion Hotspots shown on the maps are those identified by the Transport Planning & Policy Unit from a varied range of sources; Bus Network Reviews, GPS Data (Bus Data and ITIS Data), Traffic Information Websites as well as output from traffic models.

TRICS is a software package that challenges and validates assumptions about the transport impacts of new developments. It is the only national trip generation and analysis database, containing trip generation data and site information for around 3000 sites.

For this report the TRICS system was not used to estimate the traffic generated by a new development. It was used to estimate how many vehicles are likely to arrive and leave Tring and Watford HWRCs at the present time.

Within the TRICS database there are traffic count surveys for five Hertfordshire Household Waste Recycling Centres; Welwyn Garden City, Turnford, Royston, St Albans and Elstree. These are comparable sites to the two in question due to region, controlling authority, land use and the timing of the surveys.

Each survey counted all traffic entering and leaving each site over the course of a week. TRICS interrogates this data in such a way that it is able to give an estimated trip rate for Hertfordshire HWRCs in general. It presents this as Trips per Hectare split into hour long time slots. By factoring in the size of a particular site it is possible to estimate how many vehicles could reasonably be expected to enter and leave the site at any given hour of the day.

TRICS output for Hertfordshire (split into Weekday and Weekend) are presented below, along with estimates for each of the sites in question.

Estimated Average number of Vehicles (Arriving then Departing)

Approximations of the area of each site were necessary for the calculations of the estimated trip generation from the TRICS database. HCC’s ConnectMaps permits the measurement of features from OS Mastermap® Topography Layer, the most precise mapping available.

The Total Area of Tring HWRC is calculated at 716.1 sq m.

The Total Area of Watford HWRC is calculated at 1228.5 sq m.

The following maps show the location of the ATCs (as red dots) and the key areas of congestion (shaded red):