Question

英语大师进来翻译这句话，顺便说说语法，谢谢。

all the less so after over half a century of constant deterioration in favour of road。
到底是公路恶化了，还是其他（例如铁路恶化了）导致有利于公路。

Answer 1

all the less so = even less so
deterioration + in favour of road
铁路使用的边缘化，人们青睐道路运输

原文后面是一个从句，修饰deterioration， 不过经过雅思范文抄袭后，从句没了变成一句独立句了。
原文是这样的：
Enlargement will have a considerable impact on demand for mobility. This
will involve greater efforts in order gradually to break the link between transport growth and economic growth and make for a modal shift, as called for by the European Council in
Gothenburg. Such a shift cannot be ordered from one day to the next, all the less so after more than half a century of constant deterioration in favour of road, which has reached such a pitch that today rail freight services are facing marginalisation (8%), with international goods trains in Europe struggling along at an average speed of 18 km/h.

which从句都是修饰deterioration的，句子可以这样翻译：
如此的交通方式转变不可能一朝一夕，尤其是大半个世纪以来铁路运输越来越边缘化，而道路运输则受到青睐。时至今日，铁路运输被边缘化只占到总运输份额的8%...

Answer 2

要看懂all the less so首先要懂得它原本的形式all the more so，all the more so是一个很正常的习语，all the表示强调，可以无视，实质就是more so，后面一般跟一个状语从句，so代指前半句的表语，意思是在此种（后半句所描述的）情况下更是如此。以下是几个例句：
You need strong nerves to play the stock markets, all the more so in the stage of economic depression.投资股市需要有强大的神经，在经济萧条时期更是如此。
She had always been silent and thoughtful, and now she was all the more so than ever.她一直就是一个沉静和深思的女孩子，现在她比以往更是如此。
It was a worrisome thing, and all the more so because there was nothing that could be done about it.这是一件令人不安的事情，而且由于对此毫无办法，就更令人不安了。

作者根据前半句的否定形式，改了这个习语，所以这个短语词典上查不到；而且由于英文前半句是否定，后半句表递进（也就是肯定）的时候，习惯跟中文相反，比如有人说“这不公平。”另一人表示赞同，中文就会说“是的，这不公平。”但英文是“no, it's not.”

所以这里存在一个经过变异的习语，并且是一个习惯与中文相反的句子，就变得很难理解，但如果我们把它还原回去肯定形式，立刻就变得很简单了：Such a change can only be achieved in a very long time, all the more so after over half a century of constant deterioration in favour of road.
后半句中的deterioration，是因为作者认为人们越来越偏爱使用公路运输，是一件坏事，所以称这个趋势的不断强化为“deterioration（恶化）”。

这句话可以用中文的习惯来翻译，就是：这样的改变不可能一夜之间完成，而在经过了半个世纪以来运输模式不断向公路运输倾斜的情况下，就更是如此了。