Evaluation of Passenger Car Emission Indexes in Relation
to Passing through the Rail-road Crossing
Mateusz Nowak
a
, Maciej Andrzejewski
b
, Sylwin Tomaszewski
c
, Paweł Daszkiewicz
d
and Patryk Urbański
e
Lukasiewicz Research Network, Rail Vehicles Institute "TABOR", Warszawska 181, Poznan, Poland
Keywords: Exhaust Emission, Rail-road Crossing, RDE, PEMS, on-Road Measurement, Route Selection, Smooth Traffic
Flow, Sustainable Transport System, Road Congestion.
Abstract: One of the crucial aspects in the vehicles exhaust emission is, often the long duration of vehicles stop phase
before the rail-road crossing before the rail vehicle passes through. During the road vehicle stop, the
combustion engine in most cases operates in idling conditions. Some drivers turns off the combustion engines
during mentioned stop time. In modern vehicles there is also the start&stop system implemented, which
automatically stops and starts the combustion engine. Combustion engine idling phase is related to inefficient
operation, where after switching the engine off, the catalytic converter could cool down, which could result
in increased emission of harmful exhaust compounds after start of the engine. The analysis made in reference
to the Poznan agglomeration, shows many places where alternative routes can be determined with regard to
the necessity of reaching the destination, when there is a road-rail crossing on the way. The purpose of the
performed work was first of all to determine the potential of reducing fuel consumption and exhaust emission
by cars as a result of the improvement in the transport system efficiency. The improvement of transport system
efficiency could be assumed as a trip duration reduction, when the driver could receive the information about
the actual state of the rail-road infrastructure.
1 INTRODUCTION
The rail-road level crossings are very important part
of transport infrastructure. There are well known non-
collision rail-road level crossings, which are the best
in case of safety and this solution is the most
comfortable, because it does not interrupt the road
vehicles trip. The non-collision level crossings are
much more expensive and need more place, which is
crucial in urban locations, that is why most of the
existing level crossings consists of railway and road
routes placed on the same level. Based on the data
from European Railway Agency and The
International Union of Railways, there are about
114,000 level crossings in the European Union and
600,000 level crossings in the world. In that case, it is
important to ensure enough safety to prevent the
accidents. According to a report Railway Safety
a
https://orcid.org/0000-0003-1966-0423
b
https://orcid.org/0000-0003-2400-4017
c
https://orcid.org/0000-0001-8460-2137
d
https://orcid.org/0000-0001-9956-644X
e
https://orcid.org/0000-0003-0143-2166
Performance in the European Union 2016, there were
2076 significant accidents in 2014, reported by the
EU-28 countries. The traditional level-crossings are a
big challenge to ensure enough safety both for train
and road vehicle users, and that cases are a subject of
scientific papers (Kobaszynska-Twardowska et al,
2018). According to polish law, there are six different
categories of rail-road level crossings, described by a
letters from A to F. The features of different
categories were actualized in the year 2015, assuming
among others the new technical specification of trains
or infrastructure control systems (Młyńczak, Folega,
2016). Assuming the basic two types of level
crossings, much higher level of safety ensure the ones
equipped with warning or protection devices, called
as active, than the ones described as passive not
equipped with warning or protection devices
(Laapotti, 2016). There are many works on improving
Nowak, M., Andrzejewski, M., Tomaszewski, S., Daszkiewicz, P. and Urba
´
nski, P.
Evaluation of Passenger Car Emission Indexes in Relation to Passing through the Rail-road Crossing.
DOI: 10.5220/0010465305790583
In Proceedings of the 7th International Conference on Vehicle Technology and Intelligent Transport Systems (VEHITS 2021), pages 579-583
ISBN: 978-989-758-513-5
Copyright
c
2021 by SCITEPRESS Science and Technology Publications, Lda. All rights reserved
579
the safety on the rail-road level crossings, which
suggest for example use both the Global Navigation
Satelite System and optical sensors for train
positioning in the railway network (Pelz, 2007). This
assumption is favourable, because assumes the use of
cheap and reliable technology. There is also another
way to improve the safety in case of proper routing of
road vehicles.
When the rail-road level crossing is closed, it
increases the road congestion, which actually is a big
problem, especially in big cities, what was reported
by Deloitte and Targeo.pl in a report on traffic jams.
In the road congestion conditions, the vehicles fuel
consumption increases and also very often the
exhaust emission occur very close to the pedestrians.
Properly developed rail-road level crossings and
surrounding infrastructure improves the efficiency of
transport system, which is in accordance with the
main objective of sustainable transport system
(Ogryzek, Adamska-Kmieć and Klimach, 2020). The
Poznan agglomeration develops the public transport
system in case of higher frequency of rail journeys,
which is another step towards the sustainable
transport system and the sustainable development of
the city (De Gruyter, Currie and Geoff Rose, 2017).
The authors made before similar, but simulation
research only in case of trip duration (Laapotti, 2016).
The results were positive in case of longer stop times
on rail-road level crossings, which occur very often in
polish conditions.
The aim of the authors was to check if makes
sense if the driver change the route to avoid standing
in road congestion. The considerations were carried
out on example of rail-road level crossing, located in
Poznan. This location has been selected, because
there is an alternative route with collision free rail-
road level crossing in the close surroundings. The
ecological and economic analysis was carried out and
also the travel time was compared in case of the two
selected routes. The basis for this consideration were
on-road tests of passenger vehicle, performed with
PEMS (Portable Emission Measurement System)
device. That kind of measurements is very
favourable, because it reflects the actual level of
exhaust emission on selected road. Such analysis
could be performed also for whole city or region,
where the number of rail-road level crossings is much
greater and there are more alternative routes, but in
that case a macro scale model is needed. When whole
city will be assumed, there should be an analysis
made, which road transport related emission
modelling method should be chosen the
consumption-based model, EURO standard based
model or the speed dependent model (Zefreh, Torok,
2016)
2 METHODOLOGY
For the purpose of the article, the authors considered
the rail-road level crossing located on
sw. Michala str. in western part of Poznan. The
analysed route started from the intersection of
Warszawska and sw. Michala streets and finished on
a car park at the end of sw. Michala str. (Figure 1).
The selected route is characterized by high traffic
density and there is possibility of alternative route
selection without rail-road level crossing. The
distance of alternative route is about 2.1 km and it is
approximately 60% more than the primary route.
Figure 1: Analysed test routes (the primary route is marked
with blue colour and the alternative route grey); prepared
with use of www.google.com/maps (16.10.2018).
The tests were performed in real driving conditions
and the research object was a passenger vehicle
propelled with a turbocharged spark ignition engine,
compliant with Euro 6 emission standard (Figure 2).
Four different scenarios were analysed:
passage through the rail-road level crossing
without stop (described as sw. Michala I),
trip through the rail-road level crossing
including about 1,5 minute stop phase with
started combustion engine (described as sw.
Michala II),
passage through the rail-road level crossing
including about 1,5 minute stop phase with
VEHITS 2021 - 7th International Conference on Vehicle Technology and Intelligent Transport Systems
580
stopped combustion engine (described as sw.
Michala III),
trip through the roundabout Srodka and
Zawady str. (described as Roundabout Srodka-
Zawady).
The assumed stop time seems to be short in polish
conditions, but this was obtained in performed on-
road tests.
Figure 2: Test vehicle with measurement equipment.
The exhaust emission measurements were
performed with PEMS (Portable Emission
Measurement System) device: Semtech-DS,
manufactured by Sensors (Figure 3). This device is
equipped with gas analysers for specified gas
concentrations measurements and collects also
signals from exhaust flow meter, GPS, ambient
module and the vehicles OBD system. That kind of
equipment is nowadays used in additional emission
on-road tests in the vehicles homologation procedure.
Under special conditions stated in the legislative
documents, that test is called RDE. The vehicle’s
engine during all of the analysed tests was already
warmed-up
Figure 3: Exhaust emission measurement device Semtech-
DS with auxiliary components.
3 RESEARCH RESULTS
The results of performed tests are shown on Figures
4-9. The vehicle speed profiles vary because of local
differences in traffic density and the stops on
analysed rail-road level crossing (Figure 4). The
distance values of analysed test routes is about 1.3 km
in the case of primary route and about 2.1 km (+60%)
for alternative route with collision-free rail-road level
crossing (Figure 5). The duration of performed drives
vary between 132 and 253 seconds and thus the
average vehicle speed ranges from 18.4 to 42.6 km/h
(Figure 5). The shortest trip duration was recorded
during passage of the shorter route with opened rail-
road level crossing. Test with use of the longer route
result in about 35% greater drive time. The greatest
duration time values were recorded when the vehicle
was driven through shorter route with closed rail-road
level crossing (204 and 253 s). This values show, that
selection of the longer route with collision-free rail-
road level crossing even by short stop time will result
in shorter trip duration.
Figure 4: The speed profiles during performed tests.
Figure 5: Duration, distance and average speed for different
test drives.
Evaluation of Passenger Car Emission Indexes in Relation to Passing through the Rail-road Crossing
581
As it was revealed, the longer trip distance in
analyzed case could result in shorter trip duration.
The environmental performance of these passages in
terms of gaseous exhaust compounds was also
verified (Figures 6-9). The CO
2
emission, which is an
effect of fuel consumption, takes the smallest value of
approx. 235 g after passing the primary route with
opened rail-road level crossing (Figure 6). The
greatest CO
2
emission (382.5 g) was recorded after
the alternative route passage, which was about 21
24% more than after passing the shorter route with
about 1.5 minute stop. Similar dependencies are
observed in case of CO emission, but comparing to
the shorter route passage, the increase in CO emission
after passing the longer distance is 200% (Figure 7).
The smallest mass of NO
x
was emitted during passing
the shorter route with closed rail-road level crossing
and the greatest mass of this exhaust compound was
emitted during after passing the alternative route
(Figure 8). Observed dependencies could arise from
different engine operation parameters and thus
different in-cylinder temperatures which have
influence on NO
x
emission. The greatest HC mass
was measured after test performed with use of the
alternative route (Figure 8).
Obtained emission values were related to the
Euro 6 emission standard. All of performed tests in
case of CO, NO
x
and HC represent much lower
emission level than the homologation values. Great
influence on such results is that performed tests do not
include the cold start of the engine (when the engine
coolant temperature is on the level of ambient
temperature). The cold start emission will have a
great impact to the results, because of the short
distance of performed drives compared to the
homologation test cycle.
Figure 6: Summarized CO
2
emission obtained during on-
road measurements.
Figure 7: Summarized CO emission obtained during on-
road measurements.
Figure 8: Summarized NO
x
emission obtained during on-
road measurements.
Figure 9: Summarized HC emission obtained during on-
road measurements.
VEHITS 2021 - 7th International Conference on Vehicle Technology and Intelligent Transport Systems
582
Figure 10: Comparison of emission indexes reflecting the
measured emission values related to Euro 6 emission
standard.
4 CONCLUSIONS
Performed measurements show the importance of
choosing the route both from the point of view of
travel time and exhaust emissions. In analysed case,
60% longer distance result in 1330% shorter travel
time, than during drive through shorter route with 1,5
minute stop on closed rail-road level crossing. If only
trip duration will be considered, in analysed case, the
selection of longer route will benefit in shorter drive
time if the stop time will last approx. 1 minute.
The issues related to exhaust emission are more
complicated. The emission intensity depend not only
from travel time and distance, but also from engine
speed and engine load. These very complex rules
affect in the greatest mass of emitted exhaust
compounds after covering the route characterized by
longer distance and higher vehicle speed. Different
engine operating conditions higher load affect in
greatest increase (over 2 times) in case of NO
x
emission. Probably greater differences could be
observed in case of vehicles propelled with
compression ignition engines without SCR (Selective
Catalytic Reduction) system, which is responsible for
NO
x
reduction. The disadvantage of using longer
route in fuel consumption and CO
2
emission is about
62%. It could be observed, that stop on the rail-road
level crossing contributes to systematic increase of
CO
2
emission and probably three times longer stop
time on closed rail-road level crossing when the
engine is switched on, will contribute to such increase
of fuel consumption, which will make sense to use the
longer route. The performed test drives represent
much lower emission values in case of CO, NO
x
and
HC the Euro 6 homologation values. There is no clear
winner in case of the emission indexes. In case of CO,
the lowest emission index was obtained during short
trip through the opened rail-road level crossing. The
most favourable emission index for NOx were
obtained during the short trip, when the vehicle was
parked on the level crossing with started combustion
engine. The HC emission index with the lowest value
was obtained during the passage through the rail-road
level crossing with stopped combustion engine.
That assumption will have sense, when the car
driver will know, that the oncoming rail-road crossing
will be closed and should change the route. It should
be noted that mostly the stop times are significantly
longer than in analysed situation. Deeper insight in
that case will give also the research on the influence
of using different routes in that areas on ecological
and economical indexes from vehicles propelled with
compression ignition engines, which are not equipped
with three way catalytic converters as test vehicle.
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