HIGHWAY CONSTRUCTION 



PART II 



STREETS AND HIGHWAYS 



CITY STREETS 



The first work requiring the skill of the engineer is to lay out town 

 sites properly, especially with reference to the future requirements of a 

 large city where any such possibility exists. Few if any of our large 

 cities were so planned. The same principles, to a limited extent, are 

 applicable to all towns or cities. The topography of the site should be 

 carefully studied, and the street lines adapted to it. These lines 

 should be laid out systematically, with a view to convenience and 

 comfort, and also with reference to economy of construction, future 

 sanitary improvements, grades, and drainage. 



Arrangement of City Streets. Generally, the best method of 

 laying out streets is in straight lines, with frequent and regular inter- 

 secting streets, especially for the business parts of a city. When there 

 is some centrally located structure, such as a courthouse, city hall, 

 market, or other prominent building, it is very desirable to have several 

 diagonal streets leading thereto. In the residence portions of cities, 

 especially if on hilly ground, curves may with advantage replace 

 straight lines, by affording better grades at less cost of grading, and by 

 improving property through avoiding heavy embankments or cuttings. 



Width of Streets. The width of streets should be proportioned 

 to the character of the traffic that will use them. No rule can be laid 

 down by which to determine the best width of streets; but it may safely 

 be said that a street which is likely to become a commercial thorough- 

 fare should have a width of not less than 120 feet between the building 

 lines the carriage-way 80 feet wide, and the sidewalks each 20 feet 

 wide. 



In streets occupied entirely by residences a carriage-way 32 feet 

 \\idc will be ample, but the width between the building lines may be as 

 great as desired. The sidewalks may l>e any amount over 10 feet 



