delivered the opinion of the Court.
The petitioner is charged with the violation of a regulation promulgated by the Interstate Commerce Commission under 18 U. S. C. § 835.1 The. Regulation provides:
“Drivers of motor vehicles transporting any explosive, inflammable liquid, inflammable compressed *339gas, or poisonous gas shall avoid, so far as practicable, and, where feasible, by prearrangement of routes, driving into or through congested thoroughfares, places where crowds are assembled, street car tracks, tunnels, viaducts, and dangerous crossings.” 2
The statute directs that “[w]hoever knowingly violates” the Regulation shall be subject to fine or imprisonment or both.3
The indictment, in counts 1, 3, and 5, charges that petitioner on three separate occasions sent one of its trucks carrying carbon bisulphide, a dangerous and inflammable liquid, through the Holland Tunnel; a congested thoroughfare. In each instance, the truck was en route from Cascade Mills, New York, to Brooklyn, New York. On the third of these trips the load of carbon bisulphide éxploded in the tunnel and about sixty persons were injured. The indictment further states that “there were other available and more practicable routes for the transportation of said shipment, and . . . the [petitioner] well knew that tlm transportation of the shipment of carbon bisulphide . . . into the . . . Holland Tunnel was in violation of the regulations promulgated ... by the Interstate Commerce Commission . . ." 4 There is no allegation as to the feasibility of prearrangement of routes, and petitioner is not charged with any omission in that respect.
The District Court dismissed those counts of the indictment which were based upon the Regulation in ques*340tion, holding it to be invalid on the ground that the words “so far as practicable, and, where feasible” are “so vague and indefinite as to make the standard of guilt conjectural.” 90 F. Supp. 996, 998. The Court of Appeals for the Third Circuit reversed, holding that the Regulation, interpreted in conjunction with the statute, establishes a reasonably certain standard of conduct. 188 F. 2d 889. We granted certiorari. 342 U. S. 846.
A criminal statute must be sufficiently definite to give notice of the required conduct to one who would avoid its penalties, and to guide the judge in its application and the lawyer in defending one charged with its violation.5 But few words possess the precision of mathematical symbols, most statutes must deal with untold and unforeseen variations in factual situations, and the practical necessities of discharging the business of government inevitably limit the specificity with-which legislators can spell out prohibitions. Consequently, no more than a reasonable degree of certainty can be demanded. Nor is it unfair to require that one who deliberately goes perilously close to an area of proscribed conduct shall take the risk that he may cross the line.6
In Sproles v. Binford, 286 U. S. 374 (1932), these principles were applied in upholding words in a criminal statute similar to those now before us. Chief Justice Hughes, speaking for a unanimous court, there said:
“ ‘Shortest practicable route’ is not an expression too vague to be understood. The requirement of reasonable certainty does not preclude the use of ordinary, terms to express ideas which find adequate interpretation in common usage and understand*341ing. . . . The use of common experience as a glossary is necessary to meet the practical demands of legislation.” 7
The Regulation challenged here is the product of a long history of regulation of the transportation of explosives and inflammables.. Congress recognized the need for protecting the public against the hazards involved in transporting explosives as early as 1866.8 The inadequacy of the legislation then enacted led to the .passage, in 1908, of the Transportation of Explosives Act,9 which was later extended to cover inflammables.10 In accordance with that Act, the Commission in the same year issued regulations applicable to railroads. In 1934 the Commission exercised its authority under the Act to promulgate regulations governing motor trucks, including the Regulation here in question.11 In 1940 this Regulation was amended to substantially its present terminology.12 That terminology was adopted only after more than three years of study and a number of drafts. The trucking industry *342participated extensively in this process, making suggestions relating to drafts submitted to carriers and their organizations, and taking part in several hearings. The Regulation’s history indicates the careful consideration which was given to the difficulties involved in framing a regulation which would deal practically with this aspect of the problem presented by the necessary transportation of dangerous explosives on the highways.13
The statute punishes only those who knowingly violate the Regulation. This requirement of the presence of culpable intent as a necessary element of the offense does miich to destroy any force in the argument that application of the Regulation, would be so unfair- that it must be held invalid.14 That is evident from a consideration of the effect of the requirement in this case. To sustain a conviction, the Government not only must prove that petitioner could have taken another route which was both commercially practicable and appreciably safer (in its avoidance of crowded thoroughfares, etc.) than the one it did follow. It must also be shown that petitioner knew that there was such a practicable, safer route and yet deliberately took the more dangerous route through the tunnel, or that petitioner willfully neglected to exercise its duty under the Regulation to .inquire into the availability of such an alternative route.15
*343In an effort to give point to its argument, petitioner asserts that there was no practicable route its trucks might have followed which did not pass through places they were required to avoid. If it is true that in the congestion surrounding the lower Hudson there was no practicable way of crossing the River which would have avoided such points of danger to a substantially greater extent than the route taken, then petitioner has not violated the Regulation. But that is plainly a matter for proof at the trial. We are not so conversant with all the routes in that area that we may, with no. facts in the record before us, assume the allegations of the indictment to be false.16 We will not thus distort the judicial notice concept to strike down a regulation adopted only after much consultation with those affected and penalizing only those who knowingly violate its prohibition.
We therefore affirm the judgment of the Court of Appeals remanding the cause to the District Court with directions to reinstate counts 1, 3, and 5 of the indictment.
Affirmed.
18 U.S.C. § 835:
'“The Interstate Commerce Commission shall formulate regulations for the safe transportation within the limits of the jurisdiction of the United States of explosives and other dangerous articles, including flammable liquids, flammable' solids, oxidizing materials, corrosive liquids, compressed gases, and poisonous substances, which shall be binding upon all common carriers engaged in interstate or foreign commerce which transport' explosives or other dangerous articles by land, and upon all shippers making shipments of explosives or other dangerous articles via any common carrier engaged in interstate or foreign commerce by land or water.
“Such regulations Shall be in accord with the best-known practicable .means for securing safety in transit, covering the packing, marking, •loading, handling while in transit, and the precautions necessary to determine whether the material when offered is in proper condition to transport.”.
49 CFR § 197.1 (b).
“Whoever knowingly violates any such regulation shall be fined not more than $1,000 or imprisoned not more than one year, or both; and, if the death or bodily injury of any person results from such violation, shall be fined not more than $10,000 or imprisoned not more than ten years, or both.” 18 U. S. C. § 835 (sixth paragraph).
R. 2.
Lanzetta v. New Jersey, 306 U. S. 451 (1939).
Nash v. United States, 229 U. S. 373, 377 (1913); Hygrade Provision Co. v. Sherman, 266 U. S. 497, 502-503 (1925); United States v. Petrillo, 332 U.S. 1, 7-8 (1947).
Sproles v. Binford, 286 U. S. 374, 393 (1932). The provision which was there challenged and upheld was concerned basically with a requirement as to distance, a requirement applying within necessary limits of practicability, just as the Regulation here challenged is concerned basically with avoidance of designated points of. danger, within like limits of practicability.
14 Stat. 81.
35 Stat. 554, as amended, 35 Stat. 1134.
41 Stat. 1444.
49 CFR, 1938, § 85.34 (b); see Regulations for Transportation of Explosives, 2111. C. C. 351, 354 (1935).
49 CFR, 1940 Supp., § 197-7.3082: “Drivers of motor vehicles transporting inflammable liquids shall-avoid, so far as practicable, driving into or through congested thoroughfares, places where crowds are assembled, street car tracks, tunnels, viaducts and dangerous crossings. So far as practicable, this shall be accomplished by prearrangement of routes.” The section was amended to its present form in 1942. 7 Fed. Reg. 2869.
Compare United States v. Petrillo, 332 U. S. 1, 7 (1947); Miller v. Strahl, 239 U. S. 426, 434 (1915); Baltimore & Ohio R. Co. v. (Interstate Commerce Comm’n, 221 U. S. 612, 620 (1911).
Screws v. United States, 325 U. S. 91, 101-103 (1945); United States v. Ragen, 314 U. S. 513, 524 (1942); Gorin v. United States, 312 U. S. 19, 27-28 (1941); Omaechevarria v. Idaho, 246 U. S. 343, 348 (1918).
The officers, agents, and employees of every motor carrier concerned with the transportation Of explosives and other dangerous articles are required to “become conversant” with this and other regulations applying to such transportation. 49 CFR § 197.02.
This case is here to review the granting of a motion to dismiss the indictment. It should not be necessary to mention the familiar rule that, at this stage of the case, the allegations of the, indictment must be taken as true.