Regarding consumer products (arguably not environmental) and private construction, the EU is generally much stricter than the US (things like what can legally be called "chocolate" notwithstanding). But when it comes to state action, the general attitude is that most if not all laws mean whatever the legislature (and thus, effectively, the governing coalition, and thus, effectively what the Prime Minister and his cabinet) says they mean at that moment (party discipline is generally much stronger in the EU than in the US). If the Prime Minister and his cabinet want a high-speed rail line built through a particular area, it will get built in a particular area regardless of its environmental or other impacts, because the law authorizing it will basically be interpreted as superseding any prior law to the contrary.
That is a load of bullshit, at least for the EU countries in general.
The framework for environmental permits for larger infrastructure projects is the same in all the EU countries, as the EU puts down a set of rules for hearings, protected species and habitats, noise limits etc. But how those frames are filled out are very, very different. Some countries might have a clientilistic tradition (read corrupt), others a stronger hand of the current government (I suspect Britain here and maybe also France)
But in much of Northern Europe there is a general respect for playing by the rules and the government would seize being government very swiftly if they tried to skew the process of a major controversial project. This is especially true in countries with minority or coalition governments.
The big difference is the outlandish number of agencies involved in the US (two dozen??). In the EU you would generally have one consolidated process (or two if it is cross border), where all stakeholders are heard. The environmental laws can be stricter or looser than in the US, but there is no myriad of federal/union, state and local laws and corresponding agencies to issue permits.
And once that process is over - that's it. The permit is there, often including a number of options for the politicians to choose from. So after the permit comes a political process often over how much extra money is going to be spent on things like extra noise mitigation or other stuff the neighbors want, but can't outright demand according to he law. Some countries also have more or less tradition and possibilities for court challenges in this or earlier phases, but generally not nearly as prolific as in the US where every one of the many permits can be fought.
Now as I said, this works very differently in the individual countries. Case in point is the planned 18 km Femern Belt rail and highway tunnel between Denmark and Germany. Denmark finished her review and permits in about two years. Germany first got off to a slower start due to more political ambivalence about the project, and is one of the countries with rich possibilities to challenge the permit process in court, where it is currently bogged down. So far the project is about four years behind schedule due to this and might get further delays. But once the current challenges are settled, there is not going to be yet another challenge to some obscure storm water drain permit like in Brunswick, Maine.
Likewise with the financing, where a lot less agencies, levels of government and dedicated funding streams are likely to have to work together. For the Femern Tunnel the states have made a deal that Denmark pays for the tunnel itself but gets the toll revenue. The two countries pay for the necessary related build out on their own soil. The EU will chip in too as it is a prioritized international corridor, but with how much is not yet totally clear.
So all in all it often makes for a somewhat more streamlined process and also with clearer distinctions between the legal issues and the political issues.
