Customer Reviews

Highway Design and Traffic Safety Engineering Handbook

5 star:		(1)
4 star:		(0)
3 star:		(0)
2 star:		(0)
1 star:		(0)

 

 

HIGHWAY DESIGN AND TRAFFIC SAFETY ENGINEERING HANDBOOK Ruediger Lamm, Basil Psarianos, Theodor Mailaender

Most geometric designers believe that, if they have the Green Book and the Highway Capacity Manual on their bookshelves, they don=t need anything more other than, possibly, their client=s Geometric Design Manual. Wrong - this belief is about as useful as belief in the tooth fairy or the four-leaf clover. McGraw-Hill has just published a new book, authored by Ruediger Lamm, Basil Psarianos, Theodor Mailander et al. It contains 26 chapters running to just over 1000 pages and can be bought from www.amazon.com. For any designer who is really interested in getting road users from origin to destination in reasonable safety, this book is a must.

Lamm and his co-authors point out that design standards are nothing more than just limits and it is the combination of elements, all of which would conceivably be to values equal to or much higher than the specified minima, that dictate whether a road is truly safe or not. For example, the long tangent followed by a 120 m radius curve could, perfectly accurately, be described as being to a design speed of 60 km/h. The accident rate would, however, be awe-inspiring.

Many authors have pointed out in the past that the true hallmark of a safe design is its consistency and have offered various methods whereby the consistency of design can be evaluated. I submit that Lamm et al have provided the definitive measures of consistency of design. They go further and offer methods whereby necessary design improvements can also be quantified in terms of the enhancement in the level of safety that they bring about. To this end, they have carried out a major international study of the accident rates associated with the dimensions of the various elements of the road.

For example, with regard to horizontal alignment, they propose three criteria for evaluating the quality of design. These are:

Harmonising design speed and operating speed Achieving consistency in operating speed Providing adequate driving dynamic safety

Models are offered whereby the operating and design speeds can be assessed and, consequently, the three criteria quantified. Ultimately, design elements are classified into three levels of quality (generally good, fair or bad design) based on a comparison of the calculated values with threshold values that the authors have established as being reasonably indicative of the various levels of design.

The vertical alignment and cross-section are also exhaustively addressed with very important chapters on sight distance and three-dimensional alignment. The latter is a major problem because a perfect vertical alignment incorrectly superimposed on a perfect horizontal alignment can still have disastrous consequences, as the authors point out.

The safety audit process is still in its infancy in most countries and, where applied, it relies totally on the experience and judgment of very senior designers. AND

The Highway Design and Traffic Safety Engineering Handbook by Ruediger Lamm, Basil Psarianos andTheodor Mailaender