Air Quality Management Area 5 - Pollution in Greenstreet (A2)

Importance of Traffic Flow

Making sense of Traffic Flows

Average Annual Daily Flow (AADF)

Count point at 118 London Road, Greenstreet.
Counting traffic along the A2 between Vincent Rd and Faversham Rd [Newnham/Doddington]

AADF Year Link Length km Link Length miles Pedal Cycles Motor cycles Cars Taxis Buses Coaches
2000 7.2 4.47 118 186 11376 191
2001 7.2 4.47 24 122 10263 121
2002 7.2 4.47 28 230 11399 150
2003 7.2 4.47 25 219 10861 149
2004 7.2 4.47 22 175 11621 184
2005 7.2 4.47 22 186 10833 147
2006 7.2 4.47 34 107 10218 141
2007 7.2 4.47 27 132 11037 160
2008 7.2 4.47 34 123 10906 86
2009 7.2 4.47 39 128 10775 86
2010 7.2 4.47 19 184 12431 106
2011 7.2 4.47 16 182 12356 108
2012 7.2 4.47 15 177 12267 110
2013 7.2 4.47 15 187 12121 113
2014 7.2 4.47 12 193 12400 127
2015 7.2 4.47 30 98 10425 98
2016 7.2 4.47 30 98 10554 97
2017 7.2 4.47 30 95 10542 94
Light Goods Vehicles V2 Axle Rigid HGV V3 Axle Rigid HGV V4 or 5 Axle Rigid HGV V3 or 4 Axle Artic HGV V5 Axle Artic HGV V6 or More Axle Artic HGV All HGVs All Motor Vehicles (average per day)
2000 1884 279 66 36 43 94 85 603 14240
2001 1859 359 60 29 26 107 73 654 13019
2002 1777 317 49 95 40 93 80 674 14230
2003 1717 331 34 40 67 77 75 624 13570
2004 1842 297 50 30 37 72 53 539 14361
2005 1737 287 38 60 34 78 60 557 13460
2006 1791 356 54 38 37 113 79 677 12934
2007 2203 296 50 45 39 111 61 602 14134
2008 2077 318 42 77 21 80 50 588 13780
2009 2116 289 42 73 18 65 46 533 13638
2010 2076 340 63 62 44 106 95 710 15507
2011 2124 334 67 68 34 103 99 705 15475
2012 2212 331 72 76 26 101 104 711 15476
2013 2348 337 79 87 20 100 110 733 15502
2014 2520 323 81 89 20 92 117 723 15963
2015 1706 218 35 67 20 64 27 431 12758
2016 1842 229 33 77 21 60 28 448 13039
2017 1949 236 34 80 21 60 29 460 13140
(Counted to 2015; Official Estimates for 2016/17)

"Average" versus "Peak Flow"

Traffic is "lumpy".

Under ordinary conditions we see "peak traffic" in mornings and evenings as people go about their day to day lives (e.g. working near and far, school runs). Through the rest of the day we shop, visit, take deliveries, and so on. So lunch-times can show a lesser peak in traffic.

'Lumpiness' in traffic flows can also be made worse by, for example:-

Statistics vs reality

Statistics along the A2 in Greenstreet:

Of course, both these extremes are nonsensical and 'reality' falls somewhere in between. "Real-world" road-use is variable. However, "averages" do give us a sense of the scale of traffic using a stretch of road.

"Service Rate" of a road

Every road has a maximum number of road-users that it can handle smoothly at any given time. That is to say, the number of vehicles entering a section of road flows freely to leave that section of road without having to change speed. This is often referred to as its "service rate".

Congestion happens quickly! With each new development and expanded transport depot, congestion becomes more likely and will worsen for longer periods as even more traffic arrives.

For the A2/Greenstreet, most static obstructions (parking and deliveries) are on the east-travelling lane (to Faversham). Traffic in both directions are obstructed by traffic turning into and out of Station Road, Lynsted Lane and Frognal Lane. Junctions slow traffic flow down, sometimes to a halt. A review by Highways England (April 2019) confirms that traffic lights on busy roads can make matters worse across the whole day.

Links between traffic flow and harmful pollution

  1. Fuel. Slower traffic burns more fuel for longer and less efficiently. To cover the same distance, slow congested cars use lower gears that make an engine pump out more pollution than they would in fourth gear in free-flowing traffic.
  2. Fuel. Stationary traffic pumps out pollution from combustion until it leaves the 'stuck' piece of road.
  3. Friction. Moving traffic rubs rubber compound tyres against the tarmac road surface and both surfaces wear down and create very fine particles of damaging particulate matter (P.M.).
  4. Friction. Repeated braking as vehicles stop and start through traffic queues release even more very fine particles from brake-pads and discs, including metals.

PM2.5: The most worrying types of pollution created by road-users falls into a the very fine-sized particles - the Particulate Matter of 2.5microns size or smaller (PM2.5). Particles of this size pass deeply into our bodies.

In our AQMAs, SBC is measuring only ONE type of PM2.5 - Nitrogen Dioxide (NOx). NOx is created by combustion of fuels and is falling nationally as engines become cleaner and electric, hybrid and hydrogen fuels take over.

SBC and other Borough Authorities miss out all the other PM2.5 particles that increase as vehicle numbers grow and as congestion increases. You can visit a page that talks about PM2.5 here.

Links between wind and concentration of pollutants - the "Canyon Effect"

The Canyon Effect. Pollution from ALL traffic is delivered to our lungs in the spaces used by pedestrians, buggies, wheel-chairs of all types and other road-users stuck in a queue using ventilation (windows or fans). Some of that pollution also finds its way into homes, shops and offices - that pollution is with us all day. Other sources of background PM2.5 include agriculture.

Under certain conditions, pollution is trapped between buildings on both sides of a road in a "canyon" and is concentrated even more at pavement level because each passing/stationary vehicle adds its pollution to what is already there from previous vehicles. This "Canyon Effect" is what we have in Ospringe, Teynham/Lynsted, Sittingbourne and Newington (the AQMAs).

The "Canyon Effect" only works when the prevailing winds blow across the line of buildings/road. The A2 runs east to west; prevailing winds mostly blow from the south. The wind, passing over our roofs trap and churn the air between the buildings. This effect works all day and night to concentrate pullutants - much, much more dangerous at times of heavy traffic and congestion.


POLICY RESPONSES

Planners and Developers talk about reducing our dependancy on cars. At times, each of these ideas has been aired and can be seductive. But the scale of the problems with the A2 and our lanes may not dent the number of cars.

Policy ideas

Government Car/Van Ownership Statistics of July 2018

Cars / vans per household

  2002 /03 2003 /04 2004 /05 2005 /06 2006 /07 2007 /08 2008 /09 2009 /10 2010 /11 2011 /12 2012 /13 2013 /14 2014 /15 2015 /16 2016 /17
Region of residence:-
South East 1.30 1.32 1.33 1.34 1.33 1.32 1.29 1.35 1.39 1.32 1.30 1.30 1.34 1.40 1.38
Rural-Urban Classification2 of residence:-
Urban Conurbation 0.93 0.94 0.96 0.98 0.98 0.96 0.94 0.95 0.94 0.92 0.95 0.96 0.98 0.99 0.98
Urban City and Town 1.13 1.15 1.16 1.19 1.20 1.20 1.18 1.18 1.20 1.17 1.17 1.18 1.18 1.21 1.25
Rural Town and Fringe 1.32 1.30 1.32 1.36 1.37 1.40 1.43 1.43 1.41 1.39 1.37 1.37 1.39 1.41 1.43
Rural Village, Hamlet and Isolated Dwelling 1.63 1.60 1.62 1.63 1.62 1.61 1.68 1.75 1.73 1.67 1.67 1.74 1.77 1.79 1.76
All areas 1.10 1.11 1.13 1.16 1.16 1.16 1.15 1.16 1.16 1.14 1.14 1.16 1.17 1.19 1.21
1. Two survey years combined, e.g. 2016 and 2017. A survey year runs from mid-January to mid-January.
2. For more information on Rural-Urban Classifications see:
https://www.gov.uk/government/collections/rural-urban-classification

On the face of these figures, people living in rural England have 45% more cars/vans per person than the national average. This reflects the reality of poor bus services and a lack of convenient access to services (shops, GPs, libraries, post offices,etc).


Information Pages

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