Tony Radalj
November 2006
INTRODUCTION
A red light infringement trial was conducted at a sample of railway level crossings in the Perth
metropolitan area. The objective of the trial was to assess road safety risks at the crossings based
on observed frequencies of vehicles passing over the crossings during the red light phase. The
sample consisted of 9 railway level crossings of which 7 were controlled by boom barriers and 2
by flashing lights. The two types of controls were thought to be associated with distinctly different
risks due to the nature of the controls. The boom barriers could be characterised by visual display
of the barrier at various positions corresponding to the magnitude of the risk, lowering of the
barrier, closure of the carriageway and raising of the barrier. Each of the positions of the barrier
could be correlated to the risk levels of collision between a vehicle and a train at the crossing. On
the other hand the railway crossings controlled by flashing lights are thought to be associated with
higher road safety risks than the crossings controlled by the boom barriers due to the lack of
physical barrier protecting vehicle movements from possible collisions with oncoming trains
during the defined red phase time period. While the positioning of the boom barriers gives the
driver reasonable indication for the approach, arrival and departure of the train with respect to the
crossing, the flashing lights controls are lacking of this guidance for the driver on the magnitude of
the risk at each point in time of the activation of the phase. The assessment of the risk is entirely
the responsibility of the driver whether to fully obey the signals, proceed through the crossing
before the train arrival or train departure or stop at the holding line and wait for the end of the
phase when the vehicle/train collision risk is nonexistent. Therefore, the risk for a vehicle/train
collision is far lower at the crossings controlled by boom barriers than at the crossings controlled
by flashing lights, mainly due to the physical protection of the barrier itself compared to the
flashing lights which does not provide such protection. Although it can be said that any red light
infringement made at any of the two types of controlled crossings carry some risks of colliding
with a train during the operation of the phases, the risks at the boom barriers crossings during
some of the phase stages could be considered to be minimal if the vehicle motion is not
constrained within the crossing area. The minimal vehicle/train collision risks are associated with
the time periods at the beginning and the end of the red phase associated with barrier movements,
lowering or raising of the barrier. On the other hand the risk of vehicle/train collision might be
quite difficult for the driver to assess due to inadequate provision of stimuli for the driver to
estimate time required for safe passage over the crossing before the train arrival. Although the time
intervals from the activation of the phase to the train arrival to the crossing might be very similar
for both type of the controls the difficulties for the drivers in assessing the risks are quite different,
more difficult at the flashing lights than at the boom barriers controlled crossings. The length of
the warning time period in both cases is approximately 21 seconds. While the 21-second period is
accompanied by the two major stimuli at the boom barriers crossings such as flashing lights and
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lowering of the barriers, the warning time period at the flashing lights crossings is supported only
by flashing lights without the physical movements of an object whose purpose is to protect the
vehicle from advancing over the crossing as it is the case with the boom barriers when the barriers
are fully lowered to the resting position. The risk of collision between a vehicle and an oncoming
train at the flashing lights controlled crossing is highly related to this inability of the driver to
assess the length of the warning period within which the risk is relatively small even if the driver
violates the traffic law and proceed through the crossing during the red phase, as this might be the
case at the boom barriers crossing at which the driver may quite safely pass over the crossing
within the approximately first 10 seconds of the phase or until the barriers are fully lowered
approximately 16 seconds into the phase.
The operation of the active control is divided into the following stages:
1.
Flashing red signals = 6 seconds
2.
Flashing red signals plus activation of the booms to fully lowered = 10 seconds
3.
Total time Flashing red signals plus booms fully lowered = 16 seconds
4.
Total minimum warning time = 21 seconds, including the minimum interval of 5 seconds to
the arrival of the train to the crossing after the boom barriers had been fully lowered.
Therefore, short vehicles that are feasible able to pass safely under the boom barriers and enter the
crossing within the interval of up to 10 seconds after activation of the phase signals will usually
have a margin of 11 seconds before arrival of a train at the crossing. It could be argued that even
in a bad case of violation of the red signals of approximately 10 seconds the driver safety would
not be significantly compromised unless traffic or other unexpected circumstances do not permit
“free” vehicle movement. However, the safety could be affected if unpredicted outcomes occur
such as sudden stoppage of traffic, vehicle defects or some other driver uncontrolled factors that
cause the vehicle not being able to clear the crossing within the period of the train arrival to the
crossing and not being able to avoid collision due to speed.
Factors that could increase the likelihood of a crash would include:

Train approach speed above the maximum permitted.

Drivers entering crossings by driving around booms.

Second train during the cycle.
Other consequences:


Damage to boom barriers
Barriers forces out of alignment into the path of road or rail vehicles
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METHODOLOGY
The vehicle red light infringement trial at the railway level crossings was conducted at the sample
of 9 metropolitan crossings, 7 of which were controlled by boom barriers and 2 controlled by
flashing lights. Vehicle details passing over the crossings and details on infringing vehicles with
respect to the operation of the signals were recorded using MetroCount 5700 classifiers. The
classifiers were electrically linked to the railway level crossing signals, being able to keep the
register of start and end of the phases and details of the vehicles passing over the crossing during
the operational times of the signals.
The data was generally collected over a 7-day period at each of the crossings in the trial.
Due to the differences in characteristics between the two types of controls separate analysis was
done on the vehicle and phase details recorded at each of the crossings. It was hypothesised that
the driver behaviours at the two types of controlled crossings would be different, resulting from
the unique constraints to driver behaviours exhibited by the controls, such as existence or nonexistence of the physical barriers like the boom barriers.
ANALYSIS
Approximately 7-day surveys at the seven crossings controlled by boom barriers resulted in
421269 vehicle details of which 4163 passed over the crossing within the signal phase operation
periods. Similarly, 21 542 vehicles were recorded at the crossings controlled by flashing lights, of
which 83 passed through the red signals. (ref Table 1).
Boom Barrier Controlled Crossings – General Descriptive Statistics
The traffic volume varied between the boom barrier crossings, ranging between 30014 vehicles at
the Harper St crossing to 102229 vehicles at the Kelvin Rd crossing. Similarly, frequency of the
number of phases observed at the crossings ranged between 917 at East St crossing to 2246 at the
Kelvin Rd crossing. Average mean phase time for the sample was 66.19 sec. with standard
deviation of 37 sec.
The number of infringements per phase at the boom barriers controlled crossings ranged from 0.14
for Harper St to 0.76 for East St. The average number of infringements across all of the crossings
in the trial was estimated at 0.36 vehicles per phase.
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Table 1. Mean phase and infringement rate per phase by crossing
Boomgate
Railway Level
Crossing
Austin Ave
East St
Fremantle Rd
Harper St
Kelvin Rd
Wannaping Rd
William St
Total
Flashing Lights
King St
Wellard Rd
Total
N of
N of
N of
Infring. Mean
SD
vehs. Infring.
Phases Rate/PhasePhase(sec)
66089
731
1791
0.41
47.29
25.19
58081
700
917
0.76
58.41
20.12
62394
533
1452
0.37
84.08
33.65
30014
304
2190
0.14
81.93
56.19
102229
1000
2246
0.45
68.42
28.39
48328
454
1437
0.32
59.43
38.58
54134
441
1384
0.32
55.57
18.20
421269
4163
11417
0.36
66.19
37.90
6469
15073
21542
31
52
83
564
189
753
0.05
0.28
0.11
81.28
173.54
104.44
17.38
69.48
55.09
Flashing Lights – General Descriptive Statistics
For flashing lights controlled crossings the mean phase time was significantly greater than for the
boom barriers controlled crossings, 104.44 sec vs. 66.19 sec. However, the number of
infringements per phase was smaller at the flashing lights crossings than at the boom barriers
crossings, 0.11 vs. 0.36 vehicles per phase. These differences in the infringement rates could be
associated with the differences in traffic volumes passing over the crossings, the traffic volume
being significantly less at the two roads with the crossings controlled by flashing lights.
Boom Barrier Distribution of Infringements
Analysis of the infringements data recorded at the boom barrier controlled crossings indicated that
the drivers were more likely to infringe at the start of the phase rather than at the end of the phase
due to characteristics of the control associated with the boom barrier (see Figure 1); that is,
opportunities for the vehicles to make movement before the barriers are in a non-obstructing
position are significantly reduced when compared to the opportunities of taking risks at the start of
the phase. The earliest time the vehicle could possible proceed over the crossings is approximately
10 seconds before the end of the signal operation and the time the boom barriers are fully lifted at
the resting position.
Most of the infringements at the start of the phase are made within the first three seconds of the
signal operations when the highest frequency of 994 was recorded after 2 seconds from the phase
activation, sharply decreasing to 88 at the point of the boom barrier lowering stage of the phase
operation. No infringements were recorded beyond the 10 seconds of the phase operation,
approximately corresponding to the half distance position of the boom barrier lowering cycle.
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1200
No. of vehicles
1000
800
600
400
200
After the start of the phase
Seconds
-1
-2
-3
-4
-5
-6
-7
-8
-10
10
9
8
7
6
5
4
3
2
1
0
Before the end of the phase
Figure 1. Frequency distribution of vehicle red light infringements at the sample of boom barrier
controlled railway level crossings
The last risk taking vehicle in the sample was observed 10 seconds from the phase start, passing
over the crossing at least 11 seconds prior to the train arrival to the crossing. Similarly, the lesser
taking risk vehicle recorded at the beginning of the end of the phase was recorded at 10 seconds
prior the end of the phase, just at the time of the boom barrier upwards movement. Due to physical
barrier and the vehicle movements from resting positions at the crossings the number of infringing
vehicles at the end of the phase was generally low. The breakdown by vehicle type indicated that
there was no significant difference in the frequency distributions of infringements during the signal
phase operation between cars and trucks (see Figure 2, below). Both type of vehicle are more
likely to infringe at the start of the phase than at the end of the phase and within the first few
second of the signal phase operation.
70
no. of cars (short vehs.)
900
60
800
50
700
600
Cars
500
Trucks
40
400
30
300
20
200
10
100
After the start of the phase
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
10
9
8
7
6
5
4
3
2
0
1
0
Before the end of the phase
Seconds
Figure 2. Distribution of infringements by vehicle type at boom barrier controlled crossings
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no. of trucks (long vehs.)
1000
Flashing Lights Distribution of Infringements
In comparison to the distribution of infringements at the boom barrier crossings, the distribution of
infringements at the crossings controlled only by flashing lights although in decreasing frequency
magnitude is more spread over the first 8 seconds of the phase (see Figure 3, below) rather than
concentrated within the first few seconds as it was the case at the boom barrier crossings. This
pattern of the infringements distributions could be explained by lack of the physical barriers,
providing opportunities for drivers to assess the risk themselves and decide whether to proceed or
stop and wait for the train passage. No infringements were observed beyond the 8th second in the
active phase. The lower risk phase time recorded at the flashing lights of 8 seconds compared to
the longest boom barrier risk time of 10 seconds observed at the boom barrier crossings could
possible be explained by driver inability to assess “safe” passage time period prior to the train
arrival without the support of some physical indicator of the high risk time period corresponding to
the lowering of the physical barriers at the boom barriers crossings.
At the boom barrier controlled crossings the upwards boom barrier movement may give indication
to the drivers the end of the risk of colliding with the train and encouraging the drivers to proceed
towards the crossing. Although according to the Policy and Guidelines (MRWA, 2001) the risk of
colliding with another train after the passage of the train that activated the flashing lights at the
flashing lights controlled crossings is non-existent a number of drivers are infringing the red light
illegally. Under the Policy no more than one train may pass over the crossing during the same
phase, however, there might be some, although very remote, possibility of risk being increased
when the same train is permitted to perform shunting in the vicinity of the crossing, passing over
the crossing more than once in the same phase.
No. of infringements
25
20
Cars
15
Trucks
10
5
0
1
2
3
4
5
6
7
8
After the start of the phase
Seconds
-3
-2
-1
Before the end
of the phase
Figure 3. Distribution of infringements by vehicle type at flashing lights controlled crossings
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The observational data obtained from the sample study suggest that drivers are making far more
risky moves at the crossings controlled by flashing lights than at the crossings controlled by boom
barriers due to inability to accurately assess length of time within the signal phase from the
activation of the phase and inability to assess events that may eventuate after the passage of the
train that initially activated the signals.
Infringement Rates
Since the number of infringements in general case depends on the traffic exposure adjustments for
the rates have been done for the differences in the exposures between the crossings in the sample
and the whole study sample. For the infringements observed after the start of the phase the number
of infringing vehicles ranged from 0.4 vehicles per phase per 100 000 vehicles travelling over the
crossing on Harper St to 1.29 vehicles per phase per 100 000 vehicles travelling over the crossing
on East St. It seems that the drivers are the most likely to go thru the phase at the East St crossing
than any other crossing. (see Table 2).
For the boom barrier controlled crossings cars were found to make slightly higher number of
infringements than trucks did, 1.05 times, 0.08 vs. 0.07 per phase per 100 000 vehicles. However,
the comparison in infringements rates between the vehicle types for the period before the end of
the phase suggest that cars are more likely to infringe than trucks. The ratio between the
infringements rates was estimated at 1.5. This difference between the rates can be explained by
ability of cars move faster from rest than trucks can do as well as that cars need less space under
the barrier to pass safely than what is required for trucks.
Table 2. Infringement rates controlled for traffic volume by vehicle type
Boomgate
Railway Level
Crossing
Austin Ave
East St
Fremantle Rd
Harper St
Kelvin Rd
Wannaping Rd
William St
Total
Flashing Lights
King St
Wellard Rd
Total
Tot. No. of vehs. Recorded
Cars
Trucks Total
N of
Phases
61081
54075
60032
28986
93740
46313
51074
395301
5008
4006
2362
1028
8489
2015
3060
25968
66089
58081
62394
30014
102229
48328
54134
421269
1791
917
1452
2190
2246
1437
1384
11417
5698
14399
20097
771
674
1445
6469
15073
21542
564
189
753
Infringement Rate per phase (inf./100000/phase)
Ratio (Cars/trucks)
After
Before
Cars
Trucks Total Cars
Trucks Total After
Before
0.53
0.55
0.53
0.09
0.03
0.09
0.96
2.81
1.31
0.98
1.29
0.03
0.00
0.02
1.34
0.48
0.29
0.48
0.11
0.17
0.11
1.66
0.63
0.40
0.36
0.40
0.06
0.00
0.06
1.13
0.41
0.39
0.41
0.03
0.02
0.02
1.06
1.60
0.48
0.48
0.48
0.17
0.21
0.17
0.99
0.83
0.50
0.57
0.51
0.08
0.07
0.08
0.89
1.18
0.08
0.07
0.08
0.01
0.01
0.01
1.05
1.50
0.28
1.10
0.26
0.92
1.57
0.55
0.36
1.12
0.28
0.53
0.73
0.24
0.23
0.00
0.09
0.49
0.70
0.23
0.30
0.70
0.47
2.30
2.66
Comparisons of infringements rates between the two vehicle types at the crossings controlled by
flashing lights suggest that trucks are twice more likely to go through the signals at the start of the
phase than the cars would do while the same seem to exist for cars before the end of the phase
(ratio cars/trucks = 2.56) . The observed differences between cars and trucks in the infringement
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rates at the crossings controlled by flashing lights could possibly be explained by the differences in
stopping distances and differences in vehicle acceleration from rest.
CONCLUSIONS
Based on the vehicle data collected in the study at the seven Perth metropolitan railway level
crossings controlled by boom barriers and two Perth metropolitan crossings controlled by flashing
lights the following conclusions may be made:
1. Although a considerable large number of infringements was observed, especially at the boom
barrier crossings (4163 compared 83 at the flashing lights crossings), no infringements were
recoded that could be considered as high risks that could likely result in collisions with the
oncoming trains. The longest risky time period into the phase was observed at 10 seconds, at least
11 seconds prior to the possible arrival of the trains by which time the vehicle could easily and
safely clear the crossing, therefore avoiding a collision with the train.
2. Similar infringement rates for car drivers and truck drivers were observed at the crossings
controlled by boom barriers, apart from some differences prior to the end of the phase due to
possible vehicle acceleration differences and space constraints between the road and the barrier
during the last 10 seconds of the phase.
3. Although the sample of infringements recorded at the crossings controlled by flashing lights it
seems that truck drivers are more likely to use opportunities of the flashing lights controls to
proceed over the crossing at the start of the phase than the car drivers would do.
In reference to possible objectives in achievement of better compliance to traffic signals by
enforcements, it is recommended that further studies be conducted in order to determine
reasonable infringement criteria and guidelines that could be used in defining railway level
crossings enforcement strategies.
REFERENCES
Main Roads Western Australia (2001). Railway Crossing Protection in Western Australia Policy
and Guidelines
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