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# Highways 2

### Geometric Alignment

Question | Answer |
---|---|

What would be the notation for a stationing distance 1258.5m? | 1 + 258.500 |

On what basis is the 85th percentile speed selected as the design speed of the road? | Most appropriate choice the use of 99th percentile would prove extremely expensive while use of 50th percentile would prove unsafe for faster travelling vehicles |

What three factors determine the design speed for rural roads? | The mandatory constraint The Layout constraint The alignment constriant |

What is sight distance? | The length of road ahead that is visible to any road user |

What is stopping sight distance? | The distance required by the driver of a vehicle travelling at the design speed to perceive and react to an unexpected situation, and to brake and stop before reaching the stationary object on the road |

What two components make up stopping sight distance? | The distance travelled during the drivers reaction time and the distance travelled during braking |

What is the stopping sight distance equal to? (Both allowing and not allowing for grade?) | Not allowing = 0.56V + (V^2/254f) Allowing = 0.56V + [V^2/254(f+-0.01G)] |

What are the four main types of intersection conditions? | Stop condition on the side road Give-way condition on the side road Vehicles on both approaches to adjust speed Traffic Signal Control |

What are the two exceptions to the typical horizontal alignment? | 1.) Straights may be omitted on continuously curving alignment which may be provided, could be used on a rural road in an mountainous landscape. 2.) Transition curves may be omitted when the large-radius circular curves are used, or relatively low speeds |

What is the equation for tangent length? | T = R tan angle/2 |

What is the equation for the curve length? | L = pie/180 x R x angle |

What is the equation for the middle ordinate? | M = R (1 - cos (angle/2)) |

What are the measures of the tightness of a curve? | Radius Degree of curvature |

What is the expression for the minimum radius? | Rv = 0.353V^2/e |

What is the minimum offset clearance (Ms) required? | Ms = Rv (1-cos)(90SSD/pieRv) |

What are the standard values for H1 and H2 and what are they? | H1 is the driver's eye height and the standard is 1.05m. H2 is the object height and the standard is 0.26m. |

What is the equation for a with respect for p and q, for calculating Lm? | A = p-q always a positive value |

What is the formula for X? | K x modulus P |

What is the formula for L? | L = KA |

Highway planning strategies, name the four. | 1.) The land use transportation approach,2.) the demand management approach, 3.) the car-centred approach and 4.) the public transport-centred approach. |

Name 6 of the environmental assessment areas | 1.) Air quality, 2.) Heritage, 3.) Construction disturbance, 4.) Landscape and effects 5.) Land use 6.) Traffic noise and vibration 7.) Water quality and drainage 8.) Policies and Plans 9.) Vehicle travellers |

The demand for highway schemes depend on what factors? | 1.) Type of transport available to those making the journey 2.) The location of work etc relative to their homes 3.) The demographic and socio-economic characteristics of the population in question |

What three components enables the design-year volume of traffic to be estimated for the proposed highway? | 1.) Current level of traffic, 2.) Normal traffic growth and 3.) Generated traffic |