Basildon Town Centre
VISSIM Forecasting Report
March 2017
Title
Sub title (inc Bridge no.)
Date
Basildon Town Centre VISSIM Forecasting Report
i
Document Control Sheet
Document prepared by:
Transport Planning
T
01245
Senior Transport Planner Victoria House
E
essexhighways.org
Chelmsford
CM1 1JR
W
www.essex.gov.uk/highways
Report Title
Basildon VISSIM Forecasting Report
Project Number
42TPEGS007
Status
Draft
Revision
0
Control Date
Record of Issue
Issue Status
Author
Date
Check
Date
Review
Date
1
Draft
12/01/17
15/02/17
16/03/17
Approved for Issue By
Date
16/03/17
Distribution
Organisation
Contact
Number of Copies
Essex County Council
1 PDF
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Basildon Town Centre VISSIM Forecasting Report
ii
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Contents
1 Background
5
1.1
Introduction
5
1.2
Study Area
5
1.3
Project Objectives
6
2 Modelling of Options
7
2.1
Introduction
7
2.2
Options Tested
8
2.3
Results
11
2.4
Traffic Growth Assumptions
13
2.5
Traffic Growth Results
14
3 Summary and Conclusions
15
Basildon Town Centre VISSIM Forecasting Report
iii
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1 Background
1.1 Introduction
Basildon Town Centre highway proposals are being progressed as part of the
Basildon Integrated Transport Package – South East Local Enterprise
Partnership (SELEP) Business Case. Part of these improvements include
aspirations arising from the Basildon Town Centre Masterplan planning
document, produced on behalf of Basildon Council. The Masterplan document
suggests modified signal control, link closures to traffic, and two-way operation
instead of existing one-way streets. In order to assess the impact of the proposed
highway changes, Essex County Council commissioned Essex Highways to
develop a town centre VISSIM model.
Three base models were developed using PTV’s VISSIM micro simulation
software and an explanation of the model build can be seen in the Basildon
VISSIM Local Model Validation Report, issued in March 2017.
1.2 Study Area
Basildon town centre is situated approximately one mile from the A127 Southend
Arterial Road and A13 London Road - both routes are key connectors to London
and the M25. The study area is primarily made up of the following key routes -
A1321 Broadmayne, A176 Nethermayne, Southernhay, and Cherrydown East.
Basildon rail station is situated to the south of the town centre, approximately five
minutes on foot from Basildon bus station. The town centre study area is
illustrated below in
Figure 1.1
Basildon Town Centre VISSIM Forecasting Report
5
Figure 1-1: Basildon town centre VISSIM model study area
1.3 Project Objectives
The key objective of this assessment is to:
Develop and assess the Town Centre Masterplan aspirations for the
network, which affect Station Road, Cherrydown East, Southernhay and
Clayhill Road.
To do this, it was necessary to produce a VISSIM model of the area that
represents current conditions during the identified three peak periods. To
understand the impact of the Masterplan aspirations, the junctions at:
Roundacre/Station Way/Fodderwick and Southernhay;
Southernhay/Clayhill Road;
Station Way/Ashdon Way; and
Cherrydown East/Clayhill Road/Car Park 13
were modelled using empirical modelling software (LinSig) to ascertain the most
effective signal control layout and whether the junctions would operationally work
with the highest possible re-routing of traffic. The revised signal layouts were then
Basildon Town Centre VISSIM Forecasting Report
6
fed into the VISSIM model to understand how re-routing may alter the overall
travel time.
2 Modelling of Options
2.1 Introduction
Three options were modelled – the proposed Masterplan improvements as
currently defined and two variants of those including additional improvements,
which were developed through the modelling process, and following numerous
discussions between client and modellers.
Figure 2-1: Basildon MasterPlan layout
Basildon Town Centre VISSIM Forecasting Report
7
LinSig modelling software was also used to obtain the best possible results from
the revised junction layouts around the proposed two-way network
circumnavigating the town centre vehicle restrictions.
2.2 Options Tested
Option 1: Proposed Masterplan improvements
The AM, PM and Saturday peak period base VISSIM models were adapted to
reflect the aspirational Masterplan layout. The Masterplan layout includes two-
way flow along Station Way, Cherrydown East, and Clayhill Road. The two-way
flow requires extensive junction layout changes to the following junctions:
Roundacre/Station Way/Fodderwick and Southernhay;
Southernhay/Clayhill Road;
Station Way/Ashdon Way; and
Cherrydown East/Clayhill Road/Car Park 13.
The proposed junction layouts can be seen in Appendix A. The revised layouts
were initially tested in LinSig to ensure they were able to cope with the expected
traffic flows forecast by VISSIM.
Model reflects the Masterplan aspirations. The following modelling alterations
were incorporated into the base model:-
Southernhay closure between Clayhill Road and Station Way to general
traffic. Buses only on this section.
Two way traffic on Station Way, Cherrydown East, and Clayhill Road
between Southernhay and Cherrydown East.
Revision of junction layout at Roundacre/Station Way/Fodderwick and
Southernhay, Southernhay/Clayhill Road, Station Way/Ashdon Way, and
Cherrydown East/Clayhill Road/Car Park 13 for traffic and pedestrian
movements.
Closure of Cherrydown East outside of Trafford House.
Option 2: Proposed Masterplan improvements plus Ghyllgrove open
As Option 1 with the addition of:
Opening Ghyllgrove access on to Cranes Farm Road. The access is
currently closed to general traffic, with only buses and taxis using this link.
Any traffic on the Whitmore Way and Ghyllgrove housing estate that might
want to travel north towards the A127, are currently required to exit on to
Basildon Town Centre VISSIM Forecasting Report
8
either Broadmayne or East Mayne. Opening up access onto Cranes Farm
Road, will allow greater route choice and alleviate pressure on
Broadmayne and East Mayne.
Ghyllgrove access onto
Cranes Farm Road
Ghyllgrove access onto
Broadmayne
Figure 2-2: Ghyllgrove access
Option 3: Proposed Masterplan improvements plus Ghyllgrove open with
pedestrian facility across Station Way at Fodderwick junction
Combines Options 1 and 2, with the addition of:
A pedestrian facility at the junction of Roundacre/Station Way/Fodderwick.
The facility will link The Icon building with Basildon rail station. The
pedestrian facility was initially not considered as part of our option testing,
as the crossing distance length is at the furthest extreme and would be
debatable whether a staggered pedestrian island facility is required
instead, however the turning circle of vehicles and constrained highway
geometry do not allow for staggered island. The staging to accommodate
the pedestrian facility also stops all major traffic movements.
Basildon Town Centre VISSIM Forecasting Report
9
Station Way Controlled
Pedestrian Facility
Figure 2-3: Station Way Pedestrian Crossing
Basildon Town Centre VISSIM Forecasting Report
10
link to page 11
2.3 Results
The results of the base modelling and option testing can be viewed in
Figure 2-4
Speed
Delay
Travel
Delay
Travel Difference
Delay
Stops (average) stopped Distance
time
Delay
Stops
stopped Vehicles Vehicles
Delay
time
between
(average) (average)
(All)
(average) (total)
(total)
(total)
(total)
(total)
(active) (arrived) (latent) Demand
total
Base and
(All) [s]
(All)
[mph]
(All) [s] (All) [km] (All) [s]
(All) [s]
(All)
(All) [s]
(All)
(All)
[s]
(latent)
(hours)
Option
am
115.1
2.6
12.4
50.3
11546
2076495 1030941
23539
450628
700
8256
1432875
719
576.80
Base
pm
106.7
2.5
13.1
48.9
12080
2071113
982837
22939
450635
645
8569
136171
88
575.31
Sat
119.0
2.7
12.0
52.9
12777
2383430 1215578
27639
540269
680
9535
992148
534
662.06
am
119.1
2.7
12.4
53.1
11577
2087956 1041507
24006
464721
728
8017
791951
452
579.99
-3.18
Option 1 pm
111.3
2.7
13.1
50.4
12058
2060092
979762
23438
443435
652
8154
203646
131
572.25
3.06
Sat
169.4
3.9
10.1
74.0
12715
2829256 1662492
38530
726591
792
9023
896753
545
785.90
-123.84
am
112.5
2.7
12.8
51.0
11636
2039825
987423
23290
447606
740
8034
282912
221
566.62
10.19
Option 2 pm
95.2
2.4
14.1
39.3
11934
1898210
829779
20509
342330
597
8118
201950
132
527.28
48.03
Sat
164.7
3.9
10.2
73.9
12805
2799600 1627109
38096
730290
819
9062
349144
263
777.67
-115.60
am
114.1
2.6
12.6
53.4
11416
2033529
999495
23046
467296
717
8040
417822
313
564.87
11.93
Option 3 pm
105.6
2.7
13.4
44.7
11915
1996695
929396
23485
393752
613
8191
69834
61
554.64
20.67
Sat
161.1
3.8
10.3
73.1
12820
2779105 1603970
37880
727762
806
9149
235988
199
771.97
-109.91
Figure 2-4: Base and Option Testing VISSIM Modelling Results
Delay (average) – Average delay for all vehicles in model.
Stops (average) – Average number of stops for all vehicles in model. Total number of stops / (number of vehicle in the network + number of vehicles that have arrived)
Speed (average) – Average Speed in mph for all vehicles in model. Total distance / total travel time
Delay Stopped (average) – Average stopped delay per vehicle in model.
Distance (total) – Total distance travelled in Km for all vehicle in model
Travel time (total) – Travel time for all vehicles in seconds
Basildon Town Centre VISSIM Forecasting Report
11
Delay (total) – Total delay for all vehicles in model.
Stops (total) – Total number of stops for all vehicles in model.
Speed (Total) – Total Speed in mph for all vehicles in model.
Delay Stopped (Total) – Total standstill time of all vehicles in model.
Vehicles (active) – Total number of vehicles in the network at the end of the simulation
Vehicles (arrived) – Total number of vehicles which have already reached their destination and have been removed from the network.
Delay (latent) – Total waiting time of vehicles from input flows and parking lots that were not used at their actual start time in the network. This value may include waiting time of
vehicles that enter the network before the end of simulation.
Demand (latent) – Number of vehicles that were not allowed to enter the network from input flows and parking lots until the end of simulation
Basildon Town Centre VISSIM Forecasting Report
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The MasterPlan aspiration is to implement Option 1, however the model suggests
that it will provide huge disbenefits to the network in the weekday AM and on
Saturday peak hours, when comparing option 1 to the base model (see
Figure
2-4) . In order to improve the impact of the Masterplan on the highway network,
the modelling of Options 2 and 3 suggests it would be beneficial to consider also
opening up the Ghyllgrove access onto Cranes Farm Road, this can be seen in
Figure 2-4 when comparing the base model to options 1, 2, and 3, although
Saturday still shows a disbenefit when comparing to the base model. A pedestrian
crossing connecting The Icon building to Basildon rail station at the junction of
Roundacre/Station Way/Fodderwick and Southernhay would improve pedestrian
accessibility in Basildon town centre and as the modelling suggests that option 3
is likely to be no worse than option 2 when compared to the existing network,
option 3 should be taken forward as the primary scheme option. Option 3 has
been tested with 2036 traffic growth to determine the longevity of the scheme.
2.4 Traffic Growth Assumptions
Traffic growth was applied to the Base and Option 3 VISSIM models, to
understand how traffic volumes may look in the year 2036. Ideally, this should be
based on the proposed Local Plan forecasts, however these were still in
development at the time of completing this work. This element could be revisited
in the future, once the information becomes available. Growth rates were
obtained from the Department for Transport’s TEMPro software. This is the best
available forecast of general trip end growth in the area, but does not contain the
geographical detail of specific development proposals, which the Local Plan
forecast will provide. Growth assumed is summarised below
in Table 2-1. The
areas that were taken from TEMPro were E02004438 and E02004443 for car
driver, these were used to generate the growth factors. The growth factors were
applied generically across the whole model.
Growth Factor to
2036
AM Peak
14%
PM Peak
15%
Saturday Peak
16%
Table 2-1: Growth Rates for year 2036
Basildon Town Centre VISSIM Forecasting Report
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2.5 Traffic Growth Results
Modelled vehicle hours during each of the peak periods gives an indication of
total travel time and latent demand (the number of vehicles unable to enter the
modelled network due to existing delay) in the various model outputs. These can
be compared between the preferred option and the base (existing) layout.
Table
2-2 provides these results for the existing and option 3 networks for 2016 and
2036.
Each of the three existing layout peak hour periods modelled have a similar
amount of travel time recorded, however the latent demand can be considerably
different. The Saturday peak hour with the existing layout had the highest number
of vehicle hours travelled (662.06 hrs) across the three base models.
Travel time total (hours)
Demand (Latent)
Existing AM
576.80
719
Existing AM - Growth
763.97
1074
Opt 3 AM
564.87
313
Opt 3 AM - Growth
768.21
579
Existing PM
575.31
88
Existing PM - Growth
945.83
508
Opt 3 PM
554.64
61
Opt 3 PM - Growth
891.07
348
Existing Saturday
662.06
534
Existing Saturday -
Growth
1126.68
1395
Opt 3 Saturday
771.97
199
Opt 3 Saturday-Growth
736.21
191
Table 2-2: Results including Traffic Growth
As illustrated
in Table 2-2, there is not huge detriment between the existing layout
and option 3. Option 3 AM with growth shows some dis-benefit when comparing
to the existing situation, however this dis-benefit is not significant and is still less
problematic than the PM peak. The existing layout modelled in 2036 suggests
that the network will struggle to cope, however, option 3 shows more resilience
with the expected traffic volume growth with fewer vehicles held on the periphery
of the model.
Basildon Town Centre VISSIM Forecasting Report
14
3 Summary and Conclusions
This Forecasting Report details the option testing undertaken by modifying the
base year VISSIM models. Option 3 should be taken forward as this provides the
best results of all the options tested.
Option 3 indicates varying degrees of benefits and dis-benefits on individual
journey routes in the AM, PM, and Saturday peak hour periods. Option 3 is reliant
upon Ghyllgrove being open to allow traffic to access Cranes Farm Road.
To understand the likely impact in 2036, a growth rate taken from TEMPro was
applied to the base year matrices in the existing layout and Option 3 models.
The study has delivered a better understanding of the likely impact of the
Masterplan on the traffic in Basildon town centre using three base models for the
weekday AM, weekday PM and Saturday peak hours. Vehicles wishing to turn
right from Broadmayne into Ghyllgrove, for instance, are likely to turn left into
Southernhay and continue the journey by turning right from Linkway, which
increases an internal town centre movement.
A general conclusion is that the network in the town would not appear to be
overly congested during the peak hours modelled, however separate to the
model testing above, our on-street observations indicate that the signalised
junctions along Broadmayne could be improved by the revalidation of SCOOT
(Split Cycle Offset Optimisation Technique). The existing SCOOT timings do not
link well between junctions or provide early green cut-offs to allow more
congested approaches to run. SCOOT validation could provide significant
benefit at very little cost.
In summary the following measures are recommended should the Masterplan
aspirations be implemented:
Opening up Ghyllgrove northern approach to allow general traffic to
access Cranes Farm Road; and
Revalidate SCOOT along the Broadmayne corridor to optimise signal
linking between junctions to minimise delay.
Basildon Town Centre VISSIM Forecasting Report
15