Appendix: Sources and calculations
Sources are the Transport Statistics Great Britain 2004 edition (TSGB) and the SRA's year book 2004-05, (SRAYB)
Average Flow
Passenger kilometres and tonne-kilometres can be converted to equivalent bus plus lorry flows by:
| (a) |
Dividing passenger-km by a bus occupancy of 20 (5 less than claimed as the occupancy of coaches leaving Victoria coach station) or 16 to obtain equivalent coach flows |
| (b) |
Dividing tonne-km by 15 (half the capacity of a 44 tonne lorry) to obtain equivalent lorry flows. |
| (c) |
Adding the results of (a) and (b) and dividing by (i) the days in the year, 365 and (ii) the track length, 32,000 km yields the average flow per track. |
The following table provides the data for the years 1999 to 2004 where the Passenger and Tonne-km are from the SRAYB.
| Year |
1999 |
2000 |
2001 |
2002 |
2003 |
2004 |
| Pass km (bn) |
38.5 |
38.2 |
39.1 |
39.7 |
40.9 |
42.4 |
| Tonne km (bn) |
19.0 |
19.0 |
20.6 |
19.9 |
20.1 |
22.0 |
| Equivalent daily bus plus lorry flows |
| (a) 20 passengers per bus |
273 |
272 |
285 |
284 |
290 |
307 |
| (b) 16 passengers per bus |
314 |
313 |
327 |
326 |
334 |
352 |
Density of use
Densities of use are calculated by dividing the Passenger-km and Tonne-km by track or lane length.
As previously, the track length of the national rail network is 32,000 km. The lane length for the motorway and trunk road systems are estimated below where the route length for 2003 is from Table 7.8 of the TSGB and where the lane lengths assume (a) motorways average 6 lanes and Trunk roads 2 lanes and (b) motorways average 7 lanes and Trunk roads 3 lanes. In calculations the higher lane lengths have been used, namely 24,300 km for motorways and 52,000 km for motorways and trunk roads.
|
Route Length, Km
|
Lane Lengths, km |
(a) |
(b) |
Motorways |
3,477 |
20862 |
24339 |
Trunk Roads |
9,340 |
18680 |
28020 |
Total |
12,817 |
39542 |
52359 |
For rail freight we have from the SRAYB 22 billion Tonne-km in 2004. Dividing by the track length provides 0.69 million tonne-km per km.
For road freight we have from TSGB table 7.4 that, in 2003, 62% of Lorry-km were are carried by the motorway and trunk road network and 40% by the motorways. Applying those numbers to the 152 billion tonne-km of freight carried on the road system as a whole (TSGB 4.4) yields 94 and 61 billion tonne-km respectively. If we set the lane lengths to 52,000 km for motorways plus trunk roads and 24,300 km for motorways so as to produce low estimates of density we obtain:
(a) 94/52 = 1.8 million tonne-km per km for motorways and trunk roads (2.6 times the rail value)
(b) 61/24.3 = 2.5 million tonne-km per km for motorways (3.6 times the rail value).
For rail passengers we have from the SRAYB 42.4bn passenger-km per year in 2004. Dividing by the track length of 32,000 km provides a density of 1.30 million Passenger-km per km.
For road TSGB table 7.4 provides the vehicle-km data (billions) in the first 3 rows of the table below. Multiplying by the occupancy data also in the table yields the passenger-km. The occupancy of 1.5 for cars and vans may be obtained by dividing the 678 bn passenger-km in cars and vans from TSGB table 1.1 by the 451 bn car plus van vehicle-km from TSGB table 7.2. The occupancy for buses and coaches is set to 16. That compares with the national average of 9 and with the occupancy of 25 for coaches leaving Victoria coach station London .
|
Cars |
Buses |
Vans |
Total |
Motorway |
70.3 |
0.46 |
10.21 |
|
Rural Trunk |
46.2 |
0.34 |
6.76 |
|
Urban Trunk |
5.1 |
0.04 |
0.7 |
|
Totals |
121.6 |
0.84 |
17.67 |
|
Occupancy |
1.5 |
16 |
1.5 |
|
Total passenger km |
182.4 |
13.4 |
26.5 |
222.3 |
| Passenger-Km M'ways |
105.4 |
7.3 |
15.3 |
128 |
Hence the densities are:
(a) 222/52 = 4.27 million passenger-km per km for motorways and trunk roads (3.3 times the rail value)
(b) 128/24.3 = 5.27 million passenger per km for motorways (4.05 times the rail value).
Return to Factsheet 1... |
