Multiple choice question for engineering
1. ______ percentage of Indian rails routes are electrified.
Answer: c [Reason:] It is the fourth largest railway network in the world by size, comprising 119,630 kilometres (74,330 mi) of total track and 92,081 km (57,216 mi) of running track over a route of 66,687 km (41,437 mi) at the end of 2015-16. Forty-five percentage of its routes are electrified, using entirely 25 kV AC electric traction. The track is mostly broad gauge with small stretches of metre and narrow gauge track. 37% of the tracks are double or multiple tracked.
2. ____________is the predominant gauge used by Indian railways.
a) Broad gauge
b) Narrow gauge
c) Metre gauge
d) Standard gauge
Answer: a [Reason:] Indian gauge 1,676 mm (5 ft 6 in) (a broad gauge) is the predominant gauge used by IR.
Broad Gauge: width 1676 mm to 1524 mm or 5’6” to 5’0”
Standard Gauge: width 1435 mm and 1451 mm or 4′-8⅟2”
Metre Gauge: width 1067 mm, 1000 mm and 915 mm or 3′-6”, 3′-33/8” and 3′-0”
Narrow Gauge: width 762 mm and 610 mm or 2′-6” and 2′-0”.
3. Sleepers (ties) are mostly made up of _______________
b) prestressed concrete
Answer: b [Reason:] Prestressed concrete is a form of concrete used in construction which is “pre-stressed” by being placed under compression prior to supporting any loads beyond its own dead weight. This compression is produced by the tensioning of high-strength “tendons” located within or adjacent to the concrete volume, and is done to improve the performance of the concrete in service.
4. __________forms the trackbed upon which railroad ties (sleepers) are laid.
a) Track ballast
b) Concrete ballast
c) Rail ballast
d) Wooden ballast
Answer: a [Reason:] It is packed between, below, and around the ties. It is used to bear the load from the railroad ties, to facilitate drainage of water, and also to keep down vegetation that might interfere with the track structure. This also serves to hold the track in place as the trains roll by. It is typically made of crushed stone, although ballast has sometimes consisted of other, less suitable materials, for example burnt clay. The term “ballast” comes from a nautical term for the stones used to stabilize a ship.
5. The shape of ballast should be_______
Answer: b [Reason:] Stones must be irregularly cut, with sharp edges, so that they properly interlock and grip the ties in order to fully secure them against movement; spherical stones cannot do this. In order to let the stones fully settle and interlock, speed limits are often lowered on sections of track for a period of time after new ballast has been laid.
6. In this form of track, the rails are welded together by utilising flash butt welding to form one continuous rail that may be several kilometres long, this type of rail is called __________
a) Continuous jointed rail
b) Merged rail
c) Continuous welded rail
d) Continuous welded rail
Answer: c [Reason:] In this form of track, the rails are welded together by utilising flash butt welding to form one continuous rail that may be several kilometres long. Because there are few joints, this form of track is very strong, gives a smooth ride, and needs less maintenance; trains can travel on it at higher speeds and with less friction. Welded rails are more expensive to lay than jointed tracks, but have much lower maintenance costs.
7. The distance shown by red line represents ______________
b) parallel way
Answer: d [Reason:] During the early days of rail, there was considerable variation in the gauge used by different systems. Today, 54.8% of the world’s railways use a gauge of 1,435 mm (4 ft 8 1⁄2 in), known as standard or international gauge. Gauges wider than standard gauge are called broad gauge; narrower, narrow gauge. Some stretches of track are dual gauge, with three (or sometimes four) parallel rails in place of the usual two, to allow trains of two different gauges to use the same track.
8. The surface of the head of each of the two rails can be maintained by using a ___________
a) rail header
b) rail trimmer
c) rail grinder
d) rail cutter
Answer: c [Reason:] A rail grinder (or rail grinder) is a maintenance of way vehicle or train used to restore the profile and remove irregularities from worn tracks to extend its life and to improve the ride of trains using the track. Rail grinders were developed to increase the lifespan of the tracks being serviced for rail corrugation. Rail grinding is a process that is done to stop the deformation due to use and friction on railroad tracks by removing deformations and corrosion.
9. The track and ballast form the ______________
a) Temporary way
b) True way
c) Rigid way
d) Permanent way
Answer: d [Reason:] The permanent way is the elements of railway lines: generally the pairs of rails typically laid on the sleepers (“ties” in American parlance) embedded in ballast, intended to carry the ordinary trains of a railway. It is described as permanent way because in the earlier days of railway construction, contractors often laid a temporary track to transport spoil and materials about the site; when this work was substantially completed, the temporary track was taken up and the permanent way installed.
10. The longest railway platforms is ______________
a) State Street subway, Chicago
b) Gorakhpur railway station, UP
c) Kharagpur, West Bengal
d) Kollam Junction, Kerala
Answer: b [Reason:] • Gorakhpur railway station, Uttar Pradesh, India:1,366.33 m (4,483 ft) (longest in the world).
• Kollam Junction, Kerala, India:1,180.5 m (3,873 ft)
• Kharagpur, West Bengal, India: 1,072.5 m (3,519 ft)
• State Street subway, Chicago, Illinois, US: 1,067 m (3,501 ft) (longest in North America)
• Bilaspur railway station, Chhattisgarh, India: 802 m (2,631 ft).
1. __________________is any work involved in fixing or unfixing any pipe, plumbing fixture or appliance including; any trap, waste or soil pipe, ventilation pipe, or overflow pipe and any pipe that supplies or is intended to supply water.
a) Domestic plumbing
c) Sanitary plumbing
d) Plastering and putting
Answer: c [Reason:] Sanitary plumbing is any work involved in fixing or unfixing any pipe, plumbing fixture or appliance including; any trap, waste or soil pipe, ventilation pipe, or overflow pipe and any pipe that supplies or is intended to supply water.
All sanitary plumbing must comply with the Building Code and, where a building consent is required; the work must be checked by the building inspector from the building control authority in your area (your local council). A code compliance certificate cannot be issued until the work has been signed off by the building inspector.
2. __________ is the highest form of decontamination.
Answer: a [Reason:] The process of rendering an article safe to handle, by cleaning with or without disinfection or sterilization. Disinfection: The process of killing or removing pathogenic micro-organisms, except for bacterial spores and prions from inanimate objects or skin, to a level which is not harmful to health.
3. Sanitary plumbing includes the installation of appliances such as dishwashers and washing machines; the replacement or repair of taps, ball valves and plugs.
Answer: b [Reason:] Sanitary plumbing does not includes the installation of appliances such as dishwashers and washing machines; the replacement or repair of taps, ball valves and plugs.
4. The lowest or weakest level of decontamination is sanitation.
Answer: b [Reason:] The strongest level of decontamination in increasing order is: Sanitation, Antiseptic, Disinfection, Sterilization.
5. The value of ‘B’ of Indian type W.C. shown in the given figure is:
a) 60 cm
b) 45 cm
c) 25 cm
d) 15 cm
Answer: b [Reason:] A flush toilet may be colloquially called a lavatory, water closet (abbreviated W.C.), loo, comfort room (abbreviated C.R.), and many other names.
A flush toilet is a toilet that disposes of human excreta (urine and feces) by using water to flush it through a drainpipe to another location for disposal, thus maintaining a separation between humans and their excreta. Flush toilets can be designed for sitting (in which case they are also called “Western” toilets) or for squatting, in the case of squat toilets. The opposite of a flush toilet is a dry, which uses no water for flushing.
6. Anti-siphonage pipe is connected to _____________
a) top of P trap W.C.
b) main soil pipe
c) bottom of P trap W.C.
d) side of water closet
Answer: c [Reason:] A vent is open at top and bottom, to facilitate exit of foul gases. It is carried at least one meter higher than the roof level. Rain water pipe: it is a pipe which carries only the rain water. Anti-siphonage pipe: it is pipe which is installed in the house drainage to preserve the water seal of traps.
7. The trap which is provided to disconnect the house drain from the street sewer is called __________
a) interceptor chamber
b) intercepting trap
c) interception manhole
d) interceptor chamber, manhole and trap
Answer: d [Reason:] A large sewer that receives flow from a number of trunk sewers and transports the flow to the wastewater treatment plant. These sewers do not connect to homes, buildings or street.
8. The diameter of a domestic sewer pipe laid at gradient 1 in 100 is recommended ________
a) 100 mm
b) 150 mm
c) 210 mm
d) 400 mm
Answer: b [Reason:] A sanitary sewer or “foul sewer” is an underground carriage system specifically for transporting sewage from houses and commercial buildings through pipes to treatment facilities or disposal. Sanitary sewers are part of an overall system called a sewage system or sewerage.
Sewage may be treated to control water pollution before discharge to surface waters. Sanitary sewers serving industrial areas also carry industrial wastewater.
1. When drawings are drawn smaller than the actual size of the objects the scale used is said to be_________
a) Enlarging scale
b) Reducing scale
c) Small scale
d) Decreasing scale
Answer: b [Reason:] Dimensions of large objects must be reduced to accommodate on standard drawing sheets. It is not any physical instrument but a ratio taken between actual and drawing object, the drawing is drawn small and this ratio is termed as reducing scale. Don’t get confused as reducing-scale is also used by surveyors for reducing chains and links to acres and roods.
2. The ratio of length of the drawing of the object to the actual length of the object is called___________
a) Resulting fraction
b) Representative figure
c) Representative fraction
d) Representative index
Answer: c [Reason:] Representative fractions are a unit-less relation between one “unit” on the map and how ever many “units” of the same type on the ground. When a 1 cm long line in a drawing sheet represents 1 m length of the actual object on the ground, the R.F is equal to 1 cm/1 m = 1/100. These are of 3 types-full scale, reduced scale and enlarged scale.
3. The scale of chords is used to measure _________
Answer: c [Reason:] Used to read angle if there is no protractor. To draw an angle, compasses describe an arc from origin with a radius taken from the 60 mark. The required angle is copied from the scale by the compasses, and an arc of this radius drawn from the sixty mark so it intersects the first arc. The line drawn from this point to the origin will be at the target angle.
4. What is the use of circular vernier as a measuring instrument?
a) Measuring small angle
b) Measuring large angle
c) Measuring required accurate angle
d) Normal angle
Answer: c [Reason:] Verniers are also extensively used to circular scales in variety of scientific instruments.
The below figure shows typical arrangement of double direct verniers.
In Fig. the scale is graduated to 10 and value of n=10 on the vernier. 10 vernier divisions = 9 main scale divisions. Hence the least count is =d/n=10/10=6 ́. The reading is 19 0 48′.
5. If the measurement required is in three units, which scale would you prefer?
Answer: c [Reason:] Diagonal scales are used when very minute distances such as 0.1 mm etc. are to be accurately measured or when measurements are required in three units; example- dm, cm and mm, or yard, foot and inch. While other options only give measurement in single unit.
6. Vernier scale consists of two important parts, vernier scale and _________
a) Secondary scale
b) Initial scale
c) Main scale
d) Large scale
Answer: c [Reason:] The scale on the larger, fixed portion of the calliper. It gives the most significant digits in the reading, while the vernier is the sliding portion giving the least significant digits in the reading. It can be further divided into sub-parts as internal jaws, external jaws, locking screw etc.
7. A room of 1728 m3 volume is shown as 216 cm3 volume on a drawing sheet. What is the R.F?
Answer: b [Reason:] Since volume is given, formula will turn as
R.F = (drawing volume/original volume)3 R.F = (216 cm3 / 1728 * (100)3 cm3)3 = 1/200.
8. The area of field is 25,000m2. Length and breadth of the field, on the map is 5cm and 5cm respectively. What is the Representative Fraction of the scale?
Answer: c [Reason:]
Area of the field =25,000m2 Area of field on the map= 5cm*5cm=25cm2 1cm2=25000/25 = 1000m2 1 cm = 31.62 m
Now Representative Fraction = 1cm /31.62m = 1/3162.
9. One furlong = ________ meters.
Answer: d [Reason:] The furlong was the distance a team of oxen could plough without resting. This was standardized to be exactly 40 rods (1 rod = 51/2 yards) or one-eighth of a mile or 660 feet given by U.S unit system. Accurately one furlong = 201.168 meters.
10. Length of scale (LOS) = ______ × ______
a) Max. Length and R.F
b) R.F and Min. length
c) R.I and Max. Length
d) E.I and Max. Length
Answer: a [Reason:] Representative fraction (R.F.) = (Length of object on the drawing)/(Actual length of the object). If the R.F is known and the maximum length of the actual area is given, then we can find the length of scale and after which the drawing is executed below the max. length of scale. It is calculated by the following formula: Length of scale = (RF x Maximum distance to be represented).
11. What is scale ratio of full size scales?
Answer: d [Reason:] As the name suggests it does not make any changes in the scale, no increment or decrement to the figure is done. The dimensions for drawing will be full, same in proportion and size as the actual object dimensions.
12. For a plain scale, RF = ¼ and M.L = 5decimeters, what is LOS?
a) 1.25 cm
b) 12.5 cm
c) 12.5 m
Answer: b [Reason:] LOS = R.F*M.L = 1/4*5 *10 cm (Since 1dm = 10 cm)
= 12.5 cm.
1. ___________are multi-view technical drawings that contain special views of a part or parts, that reveal interior features.
a) 3d drawing
b) Isometric drawing
c) Hatched drawing
d) Sectional drawings
Answer: d [Reason:] Sectional views are an important aspect of design and documentation since it is used to improve clarity and reveal interior features of parts. Sectional drawings are multi-view technical drawings that contain special views of a part or parts that reveal interior features. A primary reason for creating a section view is the elimination of hidden lines, so that a drawing can be more easily understood or visualized. Traditional section views are based on the use of an imaginary cutting plane that cuts through the object to reveal interior features.
2. Which statement is true regarding the figure given below?
a) Full section view, where the section plane go completely through the object
b) Half section view, where the section plane go half-way through the object
c) Offset section, where the sectional plane bent through the features that are not aligned
d) Broken-out section where the section go through part of the object
Answer: d [Reason:] A broken-out section view cuts away a portion of an assembly in a drawing view to expose the inside. Cross hatching is automatically generated on the sectioned faces of all components.
A broken-out section is part of an existing drawing view, not a separate view. A closed profile, usually a spline, defines the broken-out section. Material is removed to a specified depth to expose inner details. Specify the depth by setting a number or by selecting geometry in a drawing view.
You cannot create a broken-out section on a detail, section, or alternate position view. If you create a broken-out section of an exploded view, you cannot collapse the exploded view.
The figure below consists of three questions which are as follows:-
3. Which material property is shown by the 1st figure?
a) Tie and refractory materials
d) Thermal insulation
Answer: a [Reason:] A refractory material is a material that retains its strength at high temperatures. ASTM C71 defines refractories as “…non-metallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above 1,000 °F. Refractory materials are used in for furnaces, kilns, incinerators, and reactors. They are also used to make crucibles and moulds for casting glass and metals and for surfacing flame deflector systems for rocket launch structures. Today, the iron- and steel-industry uses approximately 70% of all refractories produced.
4. Which material property is shown by the 2nd figure?
c) Electrical welding, electromagnets etc
d) Thermal insulation
Answer: c [Reason:] Electric resistance welded (ERW) pipe is manufactured by cold-forming a sheet of steel into a cylindrical shape. Current is then passed between the two edges of the steel to heat the steel to a point at which the edges are forced together to form a bond without the use of welding filler material. Initially this manufacturing process used low frequency A.C. current to heat the edges. This low frequency process was used from the 1920s until 1970. In 1970, the low frequency process was superseded by a high frequency ERW process which produced a higher quality weld.
5. Which material property is shown by the 3rd figure?
c) Sound insulation
d) Thermal insulation
Answer: a [Reason:] Concrete is a composite material composed of coarse aggregate bonded together with a fluid cement that hardens over time. Most concretes used are lime-based concretes such as Portland cement concrete or concretes made with other hydraulic cements, such as ciment fondu. However, asphalt concrete, which is frequently used for road surfaces, is also a type of concrete, where the cement material is bitumen, and polymer concretes are sometimes used where the cementing material is a polymer.
6. Given below has four figure for section line, identify which one is correct?
Answer: a [Reason:] The general purpose cast iron section line is drawn at a 45° and spaced 1.5 mm to 3 mm or more, depending on the size of the drawing. As a general rule, use 3mm spacing. Section lines are drawn as thin (.35 mm) black lines. The section lines should be evenly spaced and of equal thickness, and should be thinner than visible lines. Also, do not run section lines beyond the visible outlines or stop them too short.
7. Which figure is correct regarding the placement of dimensions or notes within the section lines?
d) Both 2nd and 3rd
Answer: b [Reason:] General Rules For Dimensioning are as follows:
1. Dimensions should NOT be duplicated, or the same information be given in two different ways.
2. No unnecessary dimensions should be used – only those needed to produce or inspect the part.
3. Dimensions should be placed at finished surfaces or important center lines.
4. Dimensions should be placed so that it is not necessary for the observer to calculate, scale, or
assume any measurement.
5. Dimensions should be attached to the view that best shows the shape of the feature to be
6. Avoid dimensioning to hidden lines wherever possible.
7. Dimensions should not be placed on the object unless that is the only clear option.
8. Overall dimensions should be placed the greatest distance away from the object so that
intermediate dimension can nest closer to the object to avoid crossing extension lines.
9. A dimension should be attached to only one view (i.e., extension lines should not connect
10. Never cross dimension lines.
11. Never cross extension lines.
12. A center line may be extended and used as an extension line.
13. Leaders should slope at a 30, 45 or 60 degree angle.
14. Dimension numbers should be centered between arrowheads, except when using stacked
dimensions then the numbers should be staggered.
15. In general, a circle is dimensioned by its diameter, an arc by its radius.
16. Holes should be located by their center lines.
17. Holes should be located in the view that shows the feature as a circle.
18. Extension lines start approximately 1/16″ from the object and extend 1/8″ past the last
8. Figure below represents a section (shaded) obtained due to intersection by a plane that is parallel to the axes of the cones, what it the section called?
Answer: b [Reason:] Hyperbola concept originated in Greek, can be defined as a set of points in a plane whose distances to two fixed points in the plane have a constant difference. It is formed by the intersection of a plane with a right circular cone. Equation of parabola: x 2 /a 2 − y 2 /b 2 = ±1.
9. The Diagonal cross section of a cylinder obtained as shown in figure will be __________
Answer: b [Reason:] The Diagonal cross section of a cylinder obtained as ellipse.
10. The cross-section perpendicular to the base but not through the vertex of a square pyramid will be a __________
Answer: c [Reason:] According to the question here (referring the figure), the green coloured line i.e. the plane, represents the axis away from the vertex through which the section is obtained. On cutting, the section obtained will be a trapezoid (shown by red dotted lines).
11. The cross-section perpendicular to the base of the shown figure is a__________
Answer: a [Reason:] Here in the figure below ED represents the perpendicular area in the triangular prism. On cutting across this area the section obtained will be rectangle type.
12. The cross-section through the vertex perpendicular to the base of the shown figure is a___________
Answer: a [Reason:] According to the question here (referring the figure), the green coloured line i.e. the plane, represents the axis through which the section is obtained. On cutting, the section obtained will be a triangle (shown by red dotted lines).
1. Normally earthwork is estimated for 30 m lead for distance and 1.5 m lift for height or depth, and this distance of 30 m and the height of 1.5 m are known as _____________
a) vertical lead and lift
b) normal lead and lift
c) horizontal lead and lift
d) transverse lead and lift
Answer: b [Reason:] Normal rate for earthwork is for 30 m lead and 1.5 m lift. For greater lead or lift the rates will be different (higher) for every unit of 30 m lead and for every unit of 1.5 m lift. The earthwork is, therefore, estimated separately for every 30 m lead and for every 1.5 m lift.
2. Cross-section of earthwork of road in banking is in the form of trapezium. Name the method to calculate the quantity of earthwork.
a) Longitudinal formula
b) Quadrilateral formula
c) Prismoidal formula
d) Trapezium formula
Answer: c [Reason:] Quantity or volume = L/6 (A1+A2+4Am).
3. Workout the quantity of earthwork for an embankment 150 m long and 10 m wide at the top. Slide slop is 2:1 and depths at each 30 m intervals are 1.2, 1.4, 1.4, 1.6, 0.60, 1.6 m.
a) 3572.9 m3
b) 4563.7 m3
c) 2572.8 m3
d) 2590.0 m3
Answer: c [Reason:] Solution-
4. To calculate the volume of earthwork from contour plan for filling a depression or pond and for cutting a hillock __________________ may be used conveniently.
a) elevation method
b) section area method
c) prismoidal formula
d) contour method
Answer: c [Reason:] The area with every contour may be found by using a Planimeter or a tracing paper containing squares. Then the prismoidal formula may be applied to calculate the volume, the distance between the two sections will be the contour intervals, i.e., the difference of level between two consecutive contours.
5. Calculate the quantity of earthwork for 200 m length for a portion of road in an uniform ground the heights of banks at the two ends being 1.00 m and 1.60 m. The formation width is 10 mm and side slope 2:1. Assume that there is no traverse slope.
a) 3276 cu m
b) 5676 cu m
c) 6757 cu m
d) 1121 cu m
Answer: a [Reason:] Quantity = (Bd+sd2) *length
Where, B=10 m, S=2,L=200 m, d=mean depth=(1+1.60)/2=1.30 m
Quantity = (10*1.3+2*1.32)*200=(13=3.38)*200=16.38*200=3276 cu m.
6. Designated point on a road where road marking or other means helps pedestrians cross safely is called?
a) Zebra crossing
b) Pedestrian crossing
Answer: b [Reason:] A pedestrian crossing or crosswalk is a place designated for pedestrians to cross a road. Crosswalks are designed to keep pedestrians together where they can be seen by motorists, and where they can cross most safely across the flow of vehicular traffic.
Marked pedestrian crossings are often found at intersections, but may also be at other points on busy roads that would otherwise be too unsafe to cross without assistance due to vehicle numbers, speed or road widths. They are also commonly installed where large numbers of pedestrians are attempting to cross (such as in shopping areas) or where vulnerable road users (such as school children) regularly cross.
7. A raised edge at the side of the roadway is known as _____________
Answer: a [Reason:] A curb, or kerb is the edge where a raised sidewalk (pavement in British English) or road median/central reservation meets a street or other roadway.
8. What is the longitudinal slope called?
Answer: c [Reason:] The grade (also called slope, incline, gradient, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper degree of “tilt”. Often slope is calculated as a ratio of “rise” to “run”, or as a fraction (“rise over run”) in which run is the horizontal distance and rise is the vertical distance.
9. A ________is a thoroughfare, route, or way on land between two places that has been paved or otherwise improved to allow travel by foot or some form of conveyance, including a motor vehicle, cart, bicycle, or horse.
Answer: d [Reason:] Roads consist of one or two roadways (British English: carriageways), each with one or more lanes and any associated sidewalks (British English: pavement) and road verges. In the Netherlands there is often a Protected Bicycle Path provided for cycling.
Roads available for use by the public may be referred to as parkways, avenues, freeways, interstates, highways, or primary, secondary, and tertiary local roads.
10. The vertical alignment of a road, expressed as a series of grades, connected by parabolic curves is called ___________
Answer: c [Reason:] The profile of a road consists of road slopes, called grades, connected by parabolic vertical curves. Vertical curves are used to provide a gradual change from one road slope to another, so that vehicles may smoothly navigate grade changes as they travel.
Sag vertical curves are those that have a tangent slope at the end of the curve that is higher than that of the beginning of the curve. When driving on a road, a sag curve would appear as a valley, with the vehicle first going downhill before reaching the bottom of the curve and continuing uphill or level.
11. ____________________is the road alignment specification which provides a substantially clear line of sight so that the driver of a vehicle.
a) Stopping sight distance
b) Safe sight distance
c) Corner sight distance (CSD)
d) Intersection sight distance
Answer: c [Reason:] Bicyclist or pedestrian waiting at the crossroad may safely anticipate the driver of an approaching vehicle. Corner sight provides an adequate time for the waiting user to either cross all lanes of through traffic, cross the near lanes and turn left, or turn right, without requiring through traffic to radically alter their speed.
12. Typical lane widths range from ______ metres to _____metres.
a) 1, 2.4
b) 10, 12.6
c) 3, 3.6
d) 8, 8.6
Answer: c [Reason:] Wider lanes and shoulders are usually used on roads with higher speed and higher volume traffic, and significant numbers of trucks and other large vehicles. Narrower lanes may be used on roads with lower speed or lower volume traffic.
Narrow lanes cost less to build and maintain, but also reduce the capacity of a road to convey traffic. On rural roads, narrow lanes are likely to experience higher rates of run-off-road and head-on collisions. Wider roads increase the time needed to walk across, and increase storm water runoff.