There are concerns regarding the impact of infrastructures (road, RR, transmission towers, etc) wildlife crossing. There are many studies and examples dealing with this topic on the Web. From what I know about the topic, sustainable development can be achieved by minimizing its impact on the environment which includes us human and wildlife. There are tons of information on the web on this topic. Some are listed below for those interested.

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http://www.wildlifeandroads.org/decisionguide/2_1_6.cfm

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http://en.wikipedia.org/wiki/Qinghai%E2%80%93Tibet_Railway

<!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;} </style> <![endif]-->Above is a picture (using Ctrl C and V, hoping the picture would appear) of a long bridge over permafrost/swamp area in Tibet with plenty of space for wildlife to cross freely underneath. In the winter, just imagine the entire area is cover with ice and snow.

This is similar to an RR/road bridge over one of the many river in the RoF. There are many river crossings along the north/south route, plenty of room for animals caribou to cross over.

An RR/road in the NS direction (i.e. on the esker corridor) may present a lesser of an obstacle for a migrating herd the NS direction, but overpasses or underpasses can be integrated into the infrastructure to facilitate herd crossing for transportation route in the EW direction as well.

In other words, the impact on the environment can be minimized with innovative engineering designs to facilitate animal crossing.

Below is a picture of caribou crossing the road somewhere in Canada. If picture is not attached, then Google should be able to locate it. Wildlife is smart and would get used a new surrounding. They would learn fast enough how to cross the road safely (e.g. off peak periods, at night?) and would not be too scare and stay away some kms from the road, as suggested by some study, due to traffic noise.

<!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;} </style> <![endif]-->https://www.youtube.com/watch?v=4tIzp7emVtQ&noredirect=1

This YouTube video is quite informative. Pictures are worth thousands words.

Enjoy,

goldhunter