This document summarizes a presentation about modeling motorway emissions. It discusses modeling emissions from individual lanes versus entire carriageways, and how lane-by-lane modeling can provide more accurate results. It also discusses the impacts of managed motorway schemes, such as converting hard shoulders to running lanes, and how these projects may affect emission and concentration profiles. Finally, it notes that the Highways Agency in the UK is updating its guidance for evaluating significant air quality impacts of transportation projects.

1. Modelling Motorway Emissions
28 November 2012
Mark Chapman
Technical Director (Air Quality)

2. 2Bureau Veritas Presentation
Introduction
► Roads → Carriageways → Lanes
► Emission Profiles
 Background, Default Assumptions, Lane by Lane Approach
► Model Verification and Adjustment Factors
► Impact Assessment
 Managed Motorways, Concentration Profiles, Influence on Results,
Considerations and Caveats

3. 3Bureau Veritas Presentation
Roads  Carriageways  Lanes
► Roads
 Single Line Emission Source
W1 E1

4. 4Bureau Veritas Presentation
Roads  Carriageways  Lanes
► 3 Lane Carriageway vs. 3 Lane by Lane
WHS W3 W1 CR E1 E3 EHSW2 E2
CRWHS EHSE2 E3E1W3 W2 W1

5. 5Bureau Veritas Presentation
Emission Profiles: Background
► Local CCTV Observation Explained: Part 1
 Asymmetrical distribution of Flow across carriageway:
• 25% of Lane 1 (Inside Lane) total
• 29% of Lane 2 (Middle Lane) total
• 46% of Lane 3 (Outside Lane) total
 Asymmetrical distribution of HGVs across carriageway:
• 5% of Lane 1 (Inside Lane) total
• 42% of Lane 2 (Middle Lane) total
• 53% of Lane 3 (Outside Lane) total

6. 6Bureau Veritas Presentation
Emission Profiles: Background
► Local CCTV Observation Explained: Part 1
 HGV influence on average speed of the lane
• HGVs restricted to 56 mph (90 kph)
• LGVs/Cars always obey the speed limit at 70 mph (112 kph)!
 Because disproportionate emissions from HGVs compared to LGVs/Cars
• Emissions distribution across the carriageway also asymmetrical

7. 7Bureau Veritas Presentation
0%
10%
20%
30%
40%
50%
60%
WHS W3 W2 W1 CR E1 E2 E3 EHS
Percentage
Lane
3 Lane Carriageway 3 Lane by Lane
Emission Profiles: Background
► 3 Lane Carriageway vs. 3 Lane by Lane

8. 8Bureau Veritas Presentation
Emission Profiles: Background
► Local CCTV Observation Explained: Part 2
 3 Lanes
• Volume and composition of vehicles were unevenly distributed across all
lanes
 4 Lanes
• Volume and composition of vehicles were also unevenly distributed
across all lanes
• Vehicles tended to remain in the same lane when a 4th Lane was available
• Shift in vehicles from Lane 3 to Lane 4 when available
• Assumed to be because vehicles were getting off at the next junction

9. 9Bureau Veritas Presentation
0%
10%
20%
30%
40%
50%
60%
WHS W3 W2 W1 CR E1 E2 E3 EHS
Percentage
Lane
3 Lane Carriageway 4 Lane Carriageway
Emission Profiles: Default Assumptions
► 3 Lane Carriageway  4 Lane Carriageway

10. 10Bureau Veritas Presentation
Emission Profiles: Lane by Lane Approach
► 3 Lane by Lane  4 Lane by Lane

11. 11Bureau Veritas Presentation
Emission Profiles: Lane by Lane Approach
► 3 Lane by Lane  4 Lane by Lane

12. 12Bureau Veritas Presentation
Model Verification and Adjustment Factors
Annual Mean NO2 Carriageway
Model Setup
Lane by Lane
Model Setup
Monitored Total 55 (@ 10m)
Monitored Background 15
Monitored Road
Component (NO2)
40
Monitored Road
Component (NOx)
101.9
Modelled Road
Component (NOx)
65.5 67.5
Adjustment Factor 1.56 1.51 (3.2% reduction)
Adjusted Modelled Total 55

13. 13Bureau Veritas Presentation
Impact Assessment: Managed Motorways
► Aim:
 Increase motorway capacity to manage increased demand for use
► CALR4
 Continuous All Lane Running
 4 Lanes [3 + Hard Shoulder] Open Continuously
► HSR
 Hard Shoulder Running
 Managed use of Hard Shoulder during peak demand periods
 Typically AM Peak, Inter-Peak and PM Peak; c.12 hrs of operation

14. 14Bureau Veritas Presentation
37
42
47
52
57
62
67
72
77
82
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
Concentration(ug/m3)
Distance from Kerb (m)
3 Lane Carriageway CALR4 Carriageway HSR Carriageway
Impact Assessment: Concentration Profiles
► Carriageway

15. 15Bureau Veritas Presentation
37
42
47
52
57
62
67
72
77
82
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
Concentration(ug/m3)
Distance from Kerb (m)
3 Lane by Lane CALR4 Lane by Lane HSR Lane by Lane
Impact Assessment: Concentration Profiles
► Lane by Lane

16. 16Bureau Veritas Presentation
Impact Assessment: Influence on Results
Carriageway Model
Setup
Lane by Lane Model
Setup
Predicted
Concentration
3 Lane (Do Minimum)
Lower Concentration
Higher Concentration
(More Exceedences)
Predicted
Concentration
4 Lane (Do Something)
Higher Concentration
(More Exceedences)
(Mitigation potentially
harder to achieve)
Lower Concentration
(Fewer Exceedences)
(Mitigation potentially
easier to achieve)
Predicted
Impact Magnitude
Higher Magnitude
(Scheme Causes More
Exceedences)
Lower Magnitude
(Scheme Causes Fewer
Exceedences)

17. 17Bureau Veritas Presentation
Impact Assessment: Influence on Results
Number of
Properties
Exposed
Distance from
Motorway Kerb
(m)
Carriageway
Model Setup
Lane by Lane
Model Setup
10 10 +51.0 +44.1
5 20 +17.7 +15.8
1 30 +2.7 +2.5
Score elsewhere in network -62.4
Net Score
+9
Overall
Worsening
0
Overall
Neutral

18. 18Bureau Veritas Presentation
Considerations and Caveats
► Influence of exhaust emission height
 Default vs. Lane by Lane variation - Adjustable within ADMS-Roads?
► Investigate influence coupled with temporal profiling:
 AM, IP, PM and OP traffic characteristics adjustment
► Dependent on local lane by lane traffic characteristics
 More survey data required
► Anyone seeking to Model Motorways for the Highways Agency should
seek guidance from HA Air Quality Advisor

19. 19Bureau Veritas Presentation
Highways Agency: Significance Criteria Update
► Highways Agency Business Objective Net Score
“The Highways Agency will not progress a major scheme which would
worsen the situation overall regarding compliance with the EU Limit
Value”
Highways Agency Business Plan 07-08
► Evaluation Criteria:
 Sum of the change in predicted concentration [impact] at relevant receptors,
where exceedence of the EU Limit Value is predicted in either Do Minimum
(Without Scheme) or Do Something (With Scheme) Scenario

20. 20Bureau Veritas Presentation
Highways Agency: Significance Criteria Update
► Review of the Highways
Agency's Approach to Evaluating
Significant Air Quality Effects
 Issued 07 September 2012
 Version: 1.1 (Final)
 Deadline for ‘comments’ closed on
5 October 2012

21. 21Bureau Veritas Presentation
Highways Agency: Significance Criteria Update
► DRAFT In Advance of Publication
of Interim Advice Note (IAN)
 Updated air quality advice
(supplementary guidance) on the
application of the test for evaluating
significant effects; for users of DMRB
Volume 11, Section 3, Part 1 (HA
207/07) ‘Air Quality’
• Includes supporting spreadsheet
• Future IAN to be used forthwith on
relevant projects in England, where
air quality assessments are
undertaken, and where such
projects have yet to be submitted
for statutory process, including the
Determination of the need for a
statutory Environmental Impact
Assessment (EIA)

22. 22Bureau Veritas Presentation
Highways Agency: Significance Criteria Update
► Need for Updated Advice?
 A (technical) review of the HA’s approach to evaluating significant air
quality impacts for the purposes of Environmental Impact Assessment
(EIA)
• To reflect national planning policy changes (National Planning Policy
Framework) whist still meeting requirements of the EIA Directive
(2011/92/EU)
 In light of this review, the HA is developing a new approach to evaluating
significant air quality impacts