Preemption

Traffic signal preemption and other technologies that seek to speed transit can have a similar effect. Faster bus travel means less fuel consumption per vehicle distance traveled. However, faster transit seiwce increases demand for transit, potentially increasing the transit load factor. 

Subchapter D - Information and Education Subchapter E - Environmental Impact Review Subchapter F - National Uniformity for Nonprescription Drugs and Preemption for Labeling or Packaging of Cosmetics Subchapter G - Safety Reports... 

Preemption. Unlike most other U.S. environmental laws, TSCA is administered and enforced exclusively by EPA. None of its rulemaking or compliance activities are delegated to the States, and TSCA rules generally preempt any comparable state (or local) laws and regulations.(15)... 

In recent years many cities have passed firearms laws more restrictive than those of the state. This frequently leads to the issue of state preemption — whether any aspect of firearms law specified by the state precludes a city or county from making its own legislation in that area. This issue is fought out on a state-by-state basis and depends on the relationship between the language of the conflicting laws and the intentions expressed by the legislature. 

According to the appeals court, The primary legal issue is whether the Legislature has completely preempted the field of regulation of handgun sales. In the absence of state preemption, every municipality is authorized by the California Constitution to exercise its police power to deal with local situations. The idea of preemption is that a lower jurisdiction (such as a city) cannot make a law that deals with a matter that a higher jurisdiction (such as the state) has already definitively covered. The lower court found that the local ordinance was not preempted. 

Preemption through judicial ruling. Local regulation may be instituted in Massachusetts if ratified by the legislature. 

Causal preemption should be distinguished from causal overdetermination. 

The federal government also preempted the motor vehicle emission control. California alone, among all the states, was able to receive waivers of federal preemption of motor vehicle control. This was permitted because California was able to prove that it had a pressing need for vehicle emission standards more stringent than those adopted by the federal government for the remainder of the country. 

Brown S. J. A. and Fletcher I. R. (1999) SHRIMP U-Pb dating of the preemption growth history of zircons from the 340 ka Whakamaru Ignimbrite, New Zealand evidence for >250 ky magma residence times. Geology 27, 1035-1038. 

By contrast, when the statute is silent on preemption, or the preemptive language is ambiguous or unclear as to the scope of the preemption, courts often undertake an implied preemption analysis in order to determine whether the legislature intended to occupy the field with legislation so sweeping that no room was left for common law, or to determine whether the common law actually conflicts with the scheme of the statute. A court may find an actual conflict where it is not possible to comply with both common law and public law, or the court may decide that common law acts as an obstacle to fulfillment of the statutory objectives. 

Envy preemption may also be behind the institution of compulsory military service, by which "the burden is spread equally and without discrimination among all the citizens. That too is a necessary result of their way of life and thought. A democratic government can do pretty well what it likes, provided that its orders apply to all and at the same moment it is the inequality of a burden, not its weight, which... 

The lack of extensive Fe-S proteins in the positive potential region may reflect their instability under oxidizing conditions and their preemption by Mn, Cu, or heme-iron sites (such as in cytochrome c), which function in this region. 

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