Even with 55% of Heathrow passengers using public transport there could be 15 million more passenger trips per year by car by 2040 than now

The government claims Heathrow can meet air quality standards in future, even with a new runway and 50% more passengers, because it will (among other changes) ensure that there are no more road vehicles than now – and by around 2031 about 55% of passengers would use public transport.  So is that likely? Looking at passengers only, not freight, and the work done by Jacobs for the Airports Commission, it seems that (2012 data) there were about 70 million passengers, about 20 million of whom were transfers (ie. they did not leave the airport). That meant slightly below 50 million passengers travelled to and from the airport, using surface transport. In 2012 about 59% of these travelled by car (ie. about 29.5 million), 41% came by public transport (28% by rail and 13% by bus or coach).  But by 2030 with a new runway, there might be around 110 million passengers, and around 33% would be international transfers. That leaves around 74 million passengers, and if 55% of them use public transport, that means about 34 million using cars. By 2040, the number using cars might be about 45 million (ie. about 15 million more per year than now).  And about 9 million using bus/coach – which is of course also on the roads. There would have to be dramatic increases in electric vehicles and improved engine technology to ensure no higher emissions in the Heathrow area.  And that is not counting freight vehicles. Or staff.  Or other increased vehicle traffic associated with the 3rd runway.



These figures include taxi trips, as well as other car trips.

The Jacobs report for the Airports Commission also states: 

7.1.4  .(Page 74) ……. Currently,  [? 2014] 59% of passengers at Heathrow travel to the airport by car or taxi, and of the 41% who travel by public transport, 28% use rail and 13% bus/coach.  Similarly, around 43% of employees at Heathrow currently commute to the airport by car/taxi, with the 47% public transport mode share split between 35% using bus and 12% using rail.

7.1.5  The HAL submission indicated that an air passenger public transport mode share target of 52% (36% rail, 17% bus/coach) was used to test the impact of the new North West Runway on the rail network and road network. Employee mode share was assumed to be 43% public transport and 47% private vehicle.



7.2.1 Our analysis predicted that public transport mode share of passenger surface access trips to/from Heathrow would increase from 41% in 2012 to 55% in 2031. [The government document put out on 25th October says 55% by 2040.  Link ]  The main change is predicted to be in the rail mode share, which is predicted to increase from 28% in 2012 to 43% in 2031. This represents a net impact of up to 2,400 additional rail trips to the airport in the AM peak hour in 2030 as a result of the new North West Runway, with up to 1,400 additional rail trips leaving the airport.



Table 2 on Page 23 of at link below



[Jacobs (Page 86) expected around 32 – 35% of interlining (ie. international transfer) passengers by 2030. That would be about 35 million interling passengers out of about 109 million. These interling passengers do not leave the airport, give no benefit to the UK economy, but do not need to travel to or from Heathrow.

The Airports Commission Final Report  (Page 251)said:   “Without expansion, the number of international transfer passengers at Heathrow is forecast to fall from 20 million a year in 2014 to 8 million or fewer by 2050; with expansion this pattern of decline could be reversed, seeing up to 30 million international transfer passengers by 2050. ”

This Airports Commission document Strategic Fit updated forecasts (pages 137 and 138) says there would be 34.4 million international to international passengers at Heathrow in 2030 (carbon traded scenario, and 23 million in 2050.


The government statement on 25th October merely said: 

“Heathrow has pledged that there will be no increase in airport-related road traffic with expansion and committed to a target of more than half of passengers using public transport to access the airport.”   Link


Some rough calculations:

Heathrow in 2012   – 70 million passengers.

Around 20 million (about 29%) were international to international transfers.

So 50 million passengers travelled to and from the airport per year, most by road or rail (excluding domestic transfers)

41% came by public transport   ie 20.5 million (of the 50 million)
28% used rail     ie  about 14 million of the 50 million
13% used bus or coach (= road)   ie. 9.1 million  ie  6.5 million of the 50 million

59% used car    ie.  29.5 million passengers out of the 50 million


Heathrow by 2030  – about 110 million passengers

Airports Commission expects around 32 – 35% would be international to international transfers. (ie about 36 million transfer passengers).  If there was a lower proportion of these transfers, more would need to travel  to and from the airport by local road and rail.

So around 74 million passengers travelling to and from the airport each year, most by road or rail.

55% using public transport     ie. about 40 million of the 74 million
43% using rail     ie.  31.8 million of the 74 million (over twice as many as now – 17 or 18 million more than now)
12% using bus or coach (= road)   ie. about 9 million of the 74 million

45% using car    ie about 34 million passengers, of the 74 million (about 4.5 million more than now – about a 15% increase.)


Heathrow by 2040 – about 128 million passengers

AC said (Page 251) there could be 30 million international to international transfers by 2050

so about 100 million passengers travelling to and from the airport each year.
55% using public transport   ie. 55 million of the 100 million 

If  43% use rail   i.e. 43 million  (compared to 14 million now- that’s 29 million more)

If 12% use bus or coach  (= road)  ie.  12 million (compared with 6.5 million now)

45% use car    ie.  45 million passengers  (About 15 million more than now – or about 53% more than now).

But the numbers needing to use public transport, or the roads, would be much higher if Heathrow does not has as much as 32 – 35% of its passengers as international to international transfers, who do not leave the airport.  The numbers could all then be up to a third higher.

AW note


Staff transport to and from Heathrow

It is worth mentioning that after the main consultation and the subsidiary extra consultation on local air quality, the Airports Commission released the Jacobs report on Surface Access:Dynamic Modelling report (dated May 2015). This is at

This analysis, by Jacobs, took the highest case for the numbers of passengers – the Airports Commission’s “carbon traded, global growth” (CT GG) scenario. (The figures are a bit higher than the “carbon traded, assessment of need” (CT AoN) scenario).   For 2030, with a 3rd runway, the CT GG figure of annual passengers is about 125 million, while the CT AoN is about 109 million.
The numbers of passengers using public transport to get to and from Heathrow in 2030 are about 73 million in the  CT AoN scenario, and about 83.9 million in the CT GG scenario.
This document also has the number on on-airport staff as about (see Tables 2.2 and 2.3 on page 8) as about 90,000 by 2030 in the CT AoN scenario, and about 115,000 [114,999]  in the CT GG scenario.  (There are perhaps – at a guess – around 67,000 on-airport staff now, but it is difficult to get a figure. It might have been about 76,000 in 2010 – but numbers fall due to greater productivity per worker year by year.  Heathrow’s own forecasts suggested about 72,100 on-airport employees with 82.5 million annual passengers, compared to about 73 million passengers now).
The 2014 Jacobs report said:  “Headline employee commuting mode share was assumed to be 43% public transport and 47% private vehicles in both options, compared to 43% public transport and 47% private transport observed in 2013.”  (Page 15 )   And (Page 74) “Similarly, around 43% of employees at Heathrow currently commute to the airport by car/taxi, with the 47% public transport mode share split between 35% using bus and 12% using rail.”  (See Page 6 )
If there are currently around  (very approximately)  76,000 on-airport staff ( link ) and 47% of them come by car, that is around 35,700 per year.
If the number of on-airport staff rose to 90,000, and 43% of them came by car, that is about 38,700 per year.   Or if 47% came by car, that would be  42.3 million.
And if the number was as many as 100,000 (let alone 115,000 staff) the number would be 43,000 per year (or  if 47% came by car, that would be 54 million). Compared to about 36 million now.
[Heathrow said in  Feb 2014  that “fewer than 65% of staff commute in single-occupancy vehicles.”  !?  Link  ]
But Heathrow says:  “A key undertaking in this is that there will be no growth in airport-related traffic on the nearby road and motorway network, facilitated by enhanced public transport as part of the Airport Surface Access Strategy (ASAS).”  Link 
Heathrow says that as a condition of the Terminal 5 Inquiry: “A limit on the number of car parking spaces for both passengers and staff to 42,000”.  [ link ]
A Heathrow presentation dated 10.11.2015  says that by 2030 trips by both staff and passengers to the airport will be 53% by public transport.  [ Link ]  ie. still 47% by public transport.
The Heathrow claim of no more cars is based on assuming a big switch in employee transport from private cars to public transport/cycling and car sharing and on that basis Heathrow have told the Commission that they do not see any need for widening the M4 and many other road schemes. The dynamic modelling report above led to another report
which answered comments made about the need for additional road infrastructure and showed the pressures they expected the road network to come under both with general development in the area and that caused by an expanded airport.

On taxi movements

comments from study by Jacobs for the Airports Commission
“Appraisal Framework Module 4. Surface Access: Heathrow Airport North West Runway.  FINAL.  FOR CONSULTATION AIRPORTS COMMISSION. 5th November 2014
Currently, 59% of passengers at Heathrow travel to the airport by car or taxi, and of the 41% who travel by public transport, 28% use rail and 13% bus/coach. Similarly, around 43% of employees at Heathrow currently commute to the airport by car/taxi, with the 47% public transport mode share split between 35% using bus and 12% using rail.
.Strategic roads
In terms of road traffic, the Jacobs model forecasted a net impact of up to 1,200 additional car/taxi trips to the airport in the AM peak hour in 2030 as a result of the new North West Runway, with up to 600 additional car/taxi trips leaving the airport. This demand was added to background traffic forecasts sourced from the DfT on sections of the strategic highway network serving the airport and then compared with estimates of capacity on network links, accounting for the impact of committed and planned Highways Agency schemes included in the core and Extended Baseline with SRA packages.


3.1.3 The sub-car mode share (i.e. the split between taxi, kiss-and-fly, short-term parking and long-term parking demand) from the 2012 CAA Heathrow passenger survey data was used to estimate a composite GC [GC means Generalised Cost] for car between each district and the airport in the base model. The complexities involved with forecasting sub-car mode share in 2030 (which would involve assumptions related to car ownership levels, background traffic congestion, availability of short- and long-term parking at the airport, average parking tariffs and dwell times, kiss-and-fly arrangements etc.) would be significant,
and the decision was taken to apply the 2012 sub-car mode share by district in the 2030 model to calculate future composite car GCs.


As a result, districts with relatively improved transport connections to the airport in 2030 were allocated an increased proportion of total airport demand, reflecting the assumption that improved transport connections would induce demand between these areas and Heathrow. This change in distribution was then fed back into the logit model to forecast the modes of transport that would be used by these trips.


3.5.7 Table 5 presents a breakdown of mode share by main regions in the UK. The analysis shows that the proposed rail improvements will generally increase public transport share across the UK. The greatest benefits are observed for trip originating from areas in the South East, East of England, and North West where the public transport share increases by over 50% from the share in 2012.  From South East (Not London), 31% of passengers are expected to access Heathrow via rail, a figure much higher than the 5% observed in 2012. The North West has a significant decrease in access by private car, with only 10% accessing Heathrow by car compared to 53% in 2012 and the proportion of passengers arriving at Heathrow by rail increasing from 35% in 2012 to 85% in 2030. The rail improvements are
also expected to reduce the number of passengers accessing the airport by car from the Inner London area, where the car mode share is predicted to reduce from 40% to 32%.

See Table 5 with % taxi etc for each region. Page 27


3.6.4 Heathrow’s own analysis shows that many taxis and private vehicles dropping off at the airport have an empty return journey. This results in approximately 40,000 additional vehicle movements a day to and from Heathrow. This represents over 25% of current car trips to and from Heathrow, so plans to reduce these trips could have an impact on the volume of airport-related trips. A setup which matches passenger to drivers that have dropped off at the airport and encourages taxi sharing is likely to reduce traffic movement. Currently, Heathrow suggest that 78% of taxi trips return empty.

Analysis shows that reducing this by 10% along with an increase in car share could reduce car trip further by up to 4%

Additional vehicle movements are allowed for empty trips generated from Kiss and fly passengers and 78% of all taxis are assumed to generate an empty return.


4 In general terms, the analysis suggests that a new North West Runway at Heathrow does not markedly increase traffic on the strategic road network. ……..

However, a noticeable increase in traffic flow as a result of the new North West Runway occurs on some specific links in the immediate vicinity of the airport, particularly on routes where ‘kiss & fly’ and taxi remain popular car sub-mode choices due to short distances between the Airport and trip origins/destinations


5.7.4 Heathrow’s proposes to reduce airport-related car trips by implementing initiatives to encourage more efficient use of private cars and taxis. These initiatives which should facilitate a reduction in the no of empty car trip and improve vehicle occupancy levels include:
 Provide sufficient car parking to meet demand with the aim to reduce discourage ‘kiss and fly’ or taxi use. Heathrow’s proposal involves expanding the terminal 5 short stay car park to 6,000 spaces for west terminal and expanding the new terminal car park to 4,000 spaces for the east terminal; and
 Develop a taxi backfilling scheme to match passengers to drivers that have dropped off at the airport and encourage taxi sharing by matching passenger journeys to similar destinations.



See also

How the government hopes air pollution will not be a block on a Heathrow 3rd runway

The Government has produced claims that adding a 3rd Heathrow runway would be compatible with air quality limits for NO2. The DfT statement on 25th October stated that the government had done more work, since the Airports Commission, and this “confirms that a new runway at Heathrow is deliverable within air quality limits, if necessary mitigation measures are put in place, in line with the ‘National air quality plan’, published in December 2015.” That air quality plan has since been judged inadequate by the High Court ruling in the case brought by ClientEarth. The DfT also said: “Heathrow’s scheme includes plans for improved public transport links and for an ultra-low emissions zone for all airport vehicles by 2025. The government will make meeting air quality legal requirements a condition of planning approval.”Lawyers Bircham Dyson Bell comment: “would you build, or invest in, a new runway if you weren’t sure it could be used?” Heathrow and the government hope that, by 2040, 55% of Heathrow passengers will be using public transport, but there is no guarantee whatsoever that legal air quality limits would in reality be met. Currently [2012 data] about 41% of Heathrow passengers use public transport (about 28% by rail and 13% bus/coach – on the road). Heathrow hopes 43% will use rail by 2030. That is estimated to mean an extra over 56 million passengers annually using public transport compared to around 29 million today, and 6 million more passengers travelling to and from the airport by car.

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