CIV5306: Road Safety Engineering - Traffic Generation - Case Study Assessment Answer

Road Safety Engineering Assignment

Assignment Task

Task A

Obtain the traffic accident data for your case study area and present them in a form which shows locations and accident types.

• You will need to obtain all the traffic accident information for your area if you haven’talready done so (see Assignment Part 1).

When obtaining the information you will have to decide for what period you require the information. You will always require the latest available information (unless, for example, you are trying to make direct comparisons with other areas which have been studies earlier). You will probably require at least three years’ information to minimise the effects of fluctuations caused by seasonal, isolated or random events. Note that these effects cannot always be entirely removed and that the number of recorded accidents does not equal the number of accidents actually occurring. Consequently, caution should be applied when drawing conclusions about the specific number and type of accidents at any location.

If a substantially greater period of data (beyond three years) is available, you should consider whether the oldest data is still relevant. For example, have there been any changes in the road network or land use within the area or nearby which could affect travel patterns and therefore affect the level of accidents? These might include a major new development, a new set of signals, a road widening, or treatment of an accident blackspot. Also, has there been any change to driving rules or to the ways in which accident data has been recorded or produced in recent years? If so it would be worthwhile obtaining data which is consistent, so long as it is for at least three years and is sufficiently up to date to be relevant.

When seeking information for particular streets and intersections, be aware of how the information is recorded. If there are three street names intersecting at one intersection, is the information recorded using only the two lowest-order alphabetic street names (or do any of the roads go by two names like Princes Highway and Main Street)? Do you have to ask for street lengths as well as intersections? Remember to include boundary roads and intersections which are within the case study area agreed to at the start of the unit.

• Present the information for the whole period you have chosen. You will need to transfer the information into a base map (or maps) of the area. Consider what are the important categories to differentiate diagrammatically.

How will you show the different numbers of accidents at the site?

Accident severity is usually a worthwhile category to indicate, as it can assist in evaluating the cost of accidents and therefore the cost-effectiveness or remedial treatments. Severity is categorised in terms such as ‘fatal’, ‘injury’ and ‘property damage’. The latter means there are no recorded injuries. The term ‘casualty’ means ‘fatals plus injuries’.

Most accident recording systems indicate accident type, in terms of the movements the road users were making prior to or when the accident occurred (see Figure 6.57.2.3, in Section 6.2 of Traffic engineering and Management). Depending on the nature of your case study area, you should attempt some indication of the types of road users and/or the movements they were making.

Further, look at the accident data and see if there are any other recorded details which stand out (e.g. is there an over-representation of accidents involving wet weather, night- timer or pedestrians?).

Undertake further investigation as necessary (see Topic 6). Does a pattern of driver behaviour begin to form? Can you see why accidents are happening? Write a clear summary of what the cause of the accidents appears to be.

Task B

Develop countermeasures for your site.

• If your site has one or more hazardous road locations, choose one for remedial treatment. If your investigations in Part A resulted in an assessment that there was no hazardous road locations, you will need to notionally add more accident statistics to it to bring it to a level of hazard which meets your adopted criteria. When doing this, add accident types which might typically apply to this type of location. For example:

Signalised intersections:rear end, right turn against oncoming traffic and/or cross traffic

Local intersection:cross traffic

Shopping centre car park:parking or unparking, intersection accidents and/or pedestrian emerging

Urban arterial road:hit pedestrian, run into parked vehicle, side swipe and/or off carriageway

Rural Road:head-on, off carriageway on bend and/or off carriageway into fixed object.

Develop a package of countermeasures for the site. You will again need to inspect the site to assist you in deciding what factors may have contributed to the particular accident problem. Inspect it from the point of view of the road users involved (e.g. unfamiliar car driver, pedestrian, bicycle rider, etc.). Remember that there may be road users with particular characteristics at this location (e.g. the pedestrians are young as it’s near a school).To assist in developing countermeasures, read the relevant sections of Topic 7.

NOTE:

During your on-site inspections, you may also become aware of some causes of potential hazard which have not resulted in recorded accidents. (e.g. there may be a tree which is blocking a set of signal lanterns, but this is not resulting in accidents yet as the combination of weather, globes in the other lanterns burnt out and/or trucks blocking visibility has not occurred yet). Road safety audits are discussed in Topic 12 as a means of identifying potential hazards before accidents occur.

Task C

Assess the cost-effectiveness of the remedial treatments for your hazardous road location, which you developed in Task B.

• Make a cost estimate of all the works involved in your proposed remedial treatment. You should be able to obtain unit cost rates for typical elements of civil engineering construction from your local Council engineering officer or, failing that, from your state road and traffic authority office which deals with estimating for accident blackspot treatments.

However, do not spend a great deal of time on this. If cost estimates cannot be readily obtained, make a (realistic) guess at the likely cost of works. The point of this exercise is to demonstrate the application of cost-benefit analysis, not to develop skills in estimating the cost of civil engineering works, so we don’t want you to spend much time on this.

• Using the techniques outlined in Topic 7, estimate the value of the crashes which are occurring at the site and which the proposed treatment is likely to reduce. (Do not include accidents which are unlikely to be affected by the proposed treatment.)

Are there any accident types which are likely to increase after the treatment goes in (e.g. signalisation of a crossroad usually reduces the incident of right angle accidents which can be costly in terms of injuries and damage, but it often leads to an increase in rear-end accidents which are less costly)?

• Using the results of (1) and (2) above, calculate the net present value (NPV) and benefit/cost ratio (BCR) of the proposed remedial treatment. To do this you will have to determine the likely annual cost reduction following treatment over the evaluation period (which you will need to estimate), reduce to a net present value, and incorporate the capital cost of treatment.

If the treatment proves to have a negative NPV (or BCR of less than 1.0), report on whether there is any part of the treatment which could be revised to improve the result. Does this involve a greater or lesser reduction in accident numbers? How many additional similar accidents would need to occur to make the treatment worthwhile?

If the treatment has a positive NPV (or BCR greater than 1.0), what is the minimum level of accident at what the project could be considered cost-effective?

The area of investigation is marked in red circle in the figure below.

The accident case No 1

Analysis of the cases of Accident

Facts known:

This accident took place when driver was changing lane at 9:15 AM, during the month of September. During September at this hour of the day good sun light is present. As it is stated that the drives are young, it is likely that that he has changed lane without giving lane change signal. The day of accident is Monday which is a working day, and since it is first day of the week. The speed of the vehicle is not high just 60 Km/hr, hence the reason of collision is changing lane by 60 km/hr into high speed lane which is always on your right. In this collision is due to driver who changed lane to his right, and he is at fault. Lane change to right is only allowed when you want to overtake, and in this case it is stated that he was not overtaking. For number of passengers are stated as 5, so it is clear that at least in one vehicle there were co-passenger, and they may be talking with each other. This distraction caused to the driver cannot be ruled out. The site of crash is shows as enclosed in square marked in red.

Figure 1 : Area of investigation is marked in cross in red. Accident location for case 1

Task B

Countermeasures and suggested remedies.

Suggested Remedies:

The reason for crash is lane change without giving signal and waiting for the right opportunity. For tracking of such offenders continuous junction area observation is must. The caution with public with come when they know that they are being observed. Policy must be made to first impose fine and then withheld license after 3 such mistakes are committed. Camera installation and 24/7 traffic monitoring and off time data analysis is recommended. Such a system will require capital expenditure for camera installation. For regular salary payout for daily video data analysis will require regular plan for salary expenditure. Part of expenditure will get recovered from the fines and based on cost analysis rate of fine imposed on such offenders can be decided.

The accident case No 2

Facts known:

This accident took place on Tuesday which is also a working day, and the time of accident is 10:10 AM. The speed of the vehicle is vey high at 80 Km/hr , hence the reason of collision is lane change to its left without waiting for vehicle coming from other direction. In this collision the driver who made the turn did not do lane change with adequate margin, and thus got hit by the vehicle traveling on its left lane. The other vehicle failed to slow down to give space for this vehicle and required clear space for turning, hence both the vehicles are at fault.

In this case the drivers are older person, so slow reaction time of the driver on the left lane can be cause for accident. The accident spot is marked as Cross. In figure no 2 the straight traffic shown hits the vehicle taking left turn as show here in green at the point marked with cross .

Figure 2 : Accident location for case 2

Task B

Countermeasures and suggested remedies.

Suggested Remedies:

The reason for crash is required lane change without giving signal well in advance to the vehicles who were traveling on lanes left to the vehicle which took left turn. Such mistakes cannot be addressed by putting any kind of signs.

One possibility is barricading one extreme left lane upto a distance of say 100m in which only left going traffic can enter. Since now straight going traffic must come to IInd lane and left going signal must come to left lane well in advance, signs on the roads will also be required.

Proposed barricading is shown in light green in Figure no 3.

Figure no 3 : Proposed barricading

The accident case No 3

Facts known:

This accident took place on Tuesday which is also a working day, and the time of accident is 1:48 PM, which is which full day light time. The speed of the vehicle is very high at 80 Km/hr; and person driving is a old person. Hence the reason of collision is colliding with a fixed object. In this collision the driver failed to notice the fixed object, and it is likely that some branch of tree must have come on the road, and he failed to notice it due to his fast speed. It can be recommended as reaction time with old age increases, so educate public to use slower driving speed as person ages.

Task B

Countermeasures and suggested remedies.

Suggested Remedies:

Policy must be made to impart continued driving education , and suggesting that aged person should reduce their driving speed. It can also be recommended that aged person in the group of senior citizen may used services of drivers.

Task C

Cost benefits analysis:

Capital expenditure for camera installation is need to be planned, and plan need to be made for regular salary payout for daily video data analysis need to be implemented.

Cost of Camera installation , and video recording is estimated as:

5 nos of camera : AUD $1000/camera , totaling $5000.

Video recoding system with storage capacity of 1 month of video = $5000* 5 = $25000

Office space for housing team of 5 software engineers who can do video analysis to issue tickets = $70000 for office building

Monthly salary = $6000/month * 5 = $30,000/Month

Cost of 5 persons for collecting money raised out of tickets = 5* $4000/month = $20,000

Total Capital expenditure = $60,000

Monthly running cost = $30,000/month

Suppose by doing video data analysis, we find 20 offender , and 20 tickets* 30 = 600 tickets are dispatched every month. With on an average $100 of fine is imposed.

Realization per month = 600*$100= $60,000

Since running cost is $30,000/month salary for software engineers and further $20,000/- for collecting money from tickets raised.

We are left with $10,000, and this video system will become free within 1 year.

Just with 5 fatal case saved, we will have at least 10 person saved for working for 20 years.

we save productive work loss of say 20years*12months*10persons = 24000 Man months.

Taking monthly salary of $4000/month, this will increase productivity of $4000*24000*5 as a factor of 4 is increase in production (20% salary payout).

This give net increase in productivity of $4000*24000*5= $480,000,000 (Approximately 480 M$).

Further there are cheap measures like installation of partition for left turn on left most on lane.

If per meter cost is $1000 , than for 200 m length, it will require $200,000/-

If one accident cane be saved per year, it will add 20 M$ and country will gain 10 times in 20 years compared to what will be invested.