2319
.pdf34.Speak on the topic: “In summer I’ll have the practice on the road maintenance activity”.
Highlight at least 5 points of your operations connected with the road maintenance.
35.Find in the text constructions with the Passive Voice. Transform the following sentences from Passive into Active Voice:
Example: The average repair jobs are done in complex (Passive). – One should do the average repair jobs in complex (Active).
36. Read the following text, find sentences containing:
a)the main information;
b)specific information.
Light-coloured rolled asphalt
The use of light-coloured road surfacings is frequently suggested as a means of reducing night-driving hazards, and the effect of the colour and texture of road surfacings on their appearance under various lighting conditions has been discussed. Concrete is, of course, intrinsically light in colour but when bituminous materials are used, special measures are necessary to produce light-coloured surfacings and several experiments have been carried out by the Road Research Laboratory to find ways of doing this.
The simplest method is to surface dress the road with a light-coloured stone. In this form of surfacing, little binder is visible and the colour is almost entirely dependent on the stone.
If it is required to lighten the colour of a mixed material such as coated macadam or fine cold asphalt on a road carrying a substantial amount of traffic, it is generally sufficient to use a light-coloured aggregate. The relatively soft binder used in these materials soon wears from the surface and, after a month or two, the stone is the predominant constituent in the surface. If the surfacing must be light-coloured from the time of laying, however, then pigments and special are necessary and the cost rises sharply: 5 per cent of titanium-dioxide pigment, for instance, will approximately treble the cost of a coated macadam wearing course. If a pale resinous binder is used instead of bitumen the increase in price will be similar.
The same considerations apply to rolled asphalt, which is the surfacing material normally chosen when traffic is very heavy. If pigment and a resinous binder are used the cost will be extremely high. It is, however, possi-
160
ble to achieve a considerable lightening of the asphalt by merely rolling light-coloured coated chipping into the surface. In the last few years the Road Research Laboratory has carried chippings in rolled asphalt and these are described in articles, together with some of the work leading up to them.
37. Give Russian equivalents to:
light-coloured rolled asphalt; night-driving hazards; to surface-dress a road; fine cold asphalt; coated macadam wearing course.
38. Translate into English.
1. Светлое дорожное покрытие используется для уменьшения риска ДТП в ночное время. 2. В некоторых случаях цвет верхнего слоя зависит от цвета наполнителя смеси. 3. Мягкое вяжущее быстро изнашивается и преобладающим компонентом верхнего слоя остается щебень. 4. Светлые смолистые вяжущие, используемые вместо битумов, увеличивают стоимость макадамного слоя. 5. Укатанный асфальт используется на дорогах с интенсивным движением.
39. Answer the questions.
1. What is light-coloured road surfacing used for? 2. What is the simplest method to make a road light-coloured? 3. What other methods to lighten road surfacing are there? 4. What binder is more expensive: bituminous or resinous? 5. What surfacing is usually chosen when traffic is heavy?
40. Read the following text. Translate it into Russian in written form. Divide text into meaningful parts and entitle them.
Simple metrological technique for checking the state of the pavements of forest roads
In order to evaluate the degree of degradation of the road surface to decide objectively on the need to repair or rebuild the pavement of a forestry road, simple test devices which are easy to operate and the corresponding metrological processes have been devised and tested.
161
Feeler gauge recording surface inequalities with a Tastograph
Here we have used the indirect method of detecting surface inequalities by using the registration of their effects on a moving vehicle. The principle of the device lies in an inert mass suspended on a system of supports which remains still in relation to the vertical oscillation of the vehicle body while the vehicle moves forward at a constant speed, the load and tyre inflation also being constant. The vertical movement of the vehicle is registered on a suitable scale on the recording strip of the Tastograph. The recording is read with the aid of a lens. The frequency, size and longitudinal position of the inequalities recorded provide an image of the degree and type of wear of the pavement. From the time point on the tastogramme, the speed of movement and the sate of the moleage recorder on the vehicle, the position of the road damage can be deduced.
But the analysis of the recording requires a lot of time. It is necessary to classify the inequalities according to their size, to compare them with standard deviations and only then can the degree of damage to the road be assessed. The sample allowing an assessment of the degree of damage to the surface is the recording carried out under the same conditions and in the same way on a new pavement, using the same device.
Electronic counter of road surface inequalities
This is the development of an idea of progressing from the transmission of impulses registered graphically by classifying them according or their size (as a percentage) and obtaining the final information using a suitable arrangement of an electronic device – the Tastograph and the electronic damage counter.
We use an electromagnetic vibration detector, the movement of which causes a membrane above the polar masses of an electromagnet to oscillate. The electronic circuit acts as a frequency breaker in the detector and its output is adapted to record the impulses in three groups based on their size. The impulses are counted by electromagnetic counters. The device is tensionally stabilized and the temperature kept constant: it also incorporates an electronic circuit to maintain a time interval of 30 seconds between recordings.
Measurements are taken at a speed of 20 km/h, as in the case of the Tastograph. The device is calibrated by running it over a good quality, new pavement, the sensitivity being adjusted so as not to record more than 10 impulses for the first type of damage. A suitable choice of test sections the position of which can be determined sufficiently well using a mileage re-
162
corder, permits a quick assessment of the surface state of forest roads while the vehicle is moving: it would otherwise be necessary to stop and descend from the vehicle. A magnetic recorder in parallel with the signal authorizes the return in the rear of the impulses counter or visual display on the oscilloscope screen.
41. Answer the questions.
1.What is used for recording surface inequalities?
2.How is the recording read?
3.What do the frequency, size and position of inequalities provide?
4.At what speed of the car are the measurement taken?
5.What information can you get by using the Tastograph and electronic counter?
163
TRAFFIC SAFETY
1. Read the title of the text. Try to guess what this text is about. Look through the text and find key words which can help you to understand the content of the text.
Traffic Safety
Traffic safety on the highway is ensured by a complex of measures:
1)by the rational construction of roads;
2)by good maintenance of the road and road structures at the time of their usage (operation);
3)by installing various warning, prohibitive and directing signs and all sorts of fences;
4)by traffic regulation;
5)by observing the established rules of traffic.
Of very great importance for the safe traffic is the correct route designing and the designing of road constructions.
While designing a highway one must provide sufficient width and height of passage, good visibility (or sight distance).
Besides this it is necessary to make provision for eliminating obstacles limiting the cross movements.
Motor-car stability on the road is achieved mainly by the sufficient cohesion between the drive wheels and the road surface and by the rational curvature design.
Pic. 40
165
2. Read and retell the following text. What signs are red-coloured, what are blue-coloured?
Signs and Signals
To ensure the tightness and safety of the traffic and for informing the driver about the conditions and peculiarities of the way the signal road signs in the form of conventional pictures are installed on the roads and streets.
The principal groups of signal signs are: the warning signs, the forbidding signs, and the directing signs.
These signs have the conventional pictures on the metal or wooden sheets the forms and dimensions of which are standard.
The signs are placed on the posts 1.4 – 2.5 m high and in the cities they may be hanged up above the carriage way of the street.
3. Read the text and say about factors that reduce capacity.
Highway Capacity
The traffic on a highway is measured by the number of vehicles passing a “traffic station” and is stated as the “volume” of traffic. In urban areas the maximum traffic day is usually a weekday; (on rural highways it frequently is Sunday). On heavily traveled roads and streets hourly counts of peak traffic may be of very great importance.
For urban freeways or major highways, traffic counts on the present streets in the area may not fully measure the volume that develops on the new facilities vehicles from some distance away may be attracted and, at times entirely new traffic may be generated. Under such circumstances, information like that developed from origin-and-destination surveys is needed if estimates are to be accurate.
It is not economically sound to design a facility to be congestion-free every hour throughout the year.
Multilane roads can be designed to meet relations between vehicle spacing and velocity. The basic capacity for a multilane highway is computed to be 2 000 cars per hour per lane, regardless of the number of lanes. Until recently, general opinion was that no more than three lanes in one direction should be used because added lanes did not contribute proportionally to capacity.
Factors that reduce capacity:
1. Lane width and edge clearance. Twelve-foot lanes and 6-foot shoulder
166
width and lateral clearances are assumed as perfect conditions. A reduction in either or both of these decreases capacity.
2.Commercial vehicles. Under all conditions, a truck utilizes more highway capacity than a passenger car. On level multilane roads one commercial vehicle (those vehicles having dual tires on the rear wheels) has the effect of two passenger cars.
3.Imperfect alignment. Imperfect alignment and breaks in the profile reduce the distance that a driver can see ahead along the road. If on a twolane road this distance is less than 1500 ft, it will not be safe to make many passing maneuvers that could otherwise be performed. This reduced passing opportunity in turn decreases capacity.
4.Grades. Brakes are assisted by gravity on upgrades and opposed by gravity on downgrades. On uphill stretches, vehicle spacings can therefore be smaller, which permits increased capacity. With grades often go restricted sight distances, which decrease capacity.
The influence of parking, turns, and pedestrians on capacity are interrelated and extremely complex.
The capacity of important intersections rather than the capacity of the street itself usually determines how many cars a major metropolitan artery can accommodate. Between intersections the street is alternately heavily loaded and largely unoccupied. These intersections, where grade separation has not been made, are almost universally controlled by traffic signals, stop sighs, or directing officers without which traffic would become completely snarled.
4. Read and study the following words:
facility – сооружение, устройство; multilane road – многопутная дорога; edge clearance – обочина дороги; shoulder – обочина дороги;
lateral clearance – обочина дороги; gravity – сила тяжести;
upgrade – подъем дороги; downgrade – скат, спуск;
to snarl – амер. приводить в беспорядок.
5. State part of speech and translate into Russian:
167
measure – measurement; state – statement; frequent – frequency; travel – travelling; count – countless; important – importance; develop – development – developed – developing; attract – attracted – attractiveness – attractive; generate – generation; accurate – accuracy; relate – relation – relationship; compute – computer; direct – directive – direction; use – useful – usefulness; add – addition; reduce – reduction; wide – width; safe – safety; perform – performance; assist – assistance; oppose – opposition; interrelate
– interrelation.
6. Use the verbs given in brackets in proper Passive forms.
1.The traffic on a highway (to measure, Present Indefinite) by the number of vehicles passing “a traffic station” and (to state, Present Indefinite) as the “volume” of traffic.
2.The basic capacity for a multilane highway (to compute, Present Indefinite) to be 2 000 cars per hour per lane.
3.Twelve-foot lanes and 6-foot shoulder widths and lateral clearance (to assume, Present Indefinite) as perfect conditions.
4.Brakes (to assist, Present Indefinite) by gravity on downgrades.
5.Between intersections the street alternately heavily (to load, Present Indefinite)
6.The intersections, where grade separation (not to make, Present Perfect), almost universally (to control, Present Indefinite) by traffic signals and so on.
7.Translate the following words combinations into English with Participle I as an attribute:
-дорога с интенсивным движением;
-информация, полученная из обследования «зарождение – назначение поездки»;
-дополнительная полоса движения;
-пониженная пропускная способность;
-повышенная пропускная способность;
-взаимосвязанные факторы;
-незагруженный участок дороги;
-беспорядочное движение.
8. Put the questions about:
168
a)the “volume” of traffic;
b)the maximum traffic day in urban and rural areas;
c)accurate estimation needed in traffic counting;
d)necessity of multilane roads;
e)factors that reduce capacity;
f)interrelated factors concerning the capacity of a road;
g)the importance of controlled intersections.
9. Read and translate the text and give its short summary:
Road capacity and special surfacings
The road capacity is calculated as the capacity under deal conditions, multiplied by reduction factors for:
-the influence of the width of the traffic lane,
-the influence of heavy vehicles,
-the distribution of the traffic on directions.
Special Surfacings
There are a lot of pavement problem, especially at intersections approaches where traffic signals installed. Regarding the rutting of surface, admixtures that have excellent low ductility properties are used in the surface layer of the pavement in an approach section (generally about 50-100 m before the pedestrian crossings). Moreover, as measures against skidding, the surface layer of the pavement is either constructed with admixtures having a high value of skidding resistance (open graded asphalt concrete and dense graded gap asphalt concrete) or with surface treatment measures such as, dressing with hard aggregates of uniform grading, limestone grit and resinoid materials, to the existing pavement surface. The results of a recent survey done on the annual occurrence of accidents before and after the adoption of a skid-proof method in Tokyo. From these results it is clear that the method is very effective, especially on rainy days.
10.Speak about the capacity of highways.
11.Read and translate the following text. Give its short summary.
169
The urban transportation problems
When the initial improvement of main rural roads had established definite flows of motor traffic, it became increasingly apparent that future growth of' the country’s highway transportation system should be on a scientific rather than a haphazard bases. City streets were in relative distress, and many rural highways were overloaded. As traffic in urban areas has increased, more and more attention has been focused on the problem created.
Transportation has greatly influenced the development of our city. With the invention of the automobile the city exploded. At first, use of the automobile was restricted largely to the existing street system - system designed without any concept of motor-vehicle movement. Gradually, the streets were improved, and the cities began to spread over the countryside. The introduction of freeways and expressways greatly accelerated the expansion. The proportion of people in urban areas had been increasing.
The urban transportation problem, which with the great increase in motor transportation, has become acute may be clarified with data accumulated by planning surveys and particularly from origin and destination studies. On an average, over 90% of the traffic that approaches our larger cities is destined to them. In terms of vehicle-miles, about half of our vast highway transport is within urban areas. Excepting intercity traffic there is, in proportion to the size of our cities, a typical “traffic radius” that measures the limit of motor movements to and from the heart of the city. Around the largest cities, its length is about 35 miles.
While the motor vehicle has enabled cities to expand outwardly, thus improving residential conditions, it has caused traffic congestion to increase alarmingly in the hearts of the business districts. Much of the congestion and impedance is due to the rectangular street pattern that involves interrupting cross traffic. Much also can be attributed to a lack of convenient and available parking space.
As for the private cars, ten times as many persons can be moved over a given street in mass-transportation vehicles as in private autos.
The facts developed about the downtown congestion problem indicate the need for a new approach. Primary attention must be focused upon the movement of people rather than the movement of vehicles. Masstransportation facilities must be improved, so that fewer automobiles will come into the downtown area. Freeway plans must include not only radial lines feeding into the downtown area, but also belt lines circling the down-
170