delivered the opinion of the Court.
Each of the defendants in error, except Gr. L1. Harrison, filed a separate suit against the plaintiffs in error for damages for personal injuries sustained when the automobile in which they were riding collided with a motor driven bus, owned and operated by plaintiffs in error, *297Chattanooga Dayton Bus Line and F. S. Wingate. The suit of GL L. Harrison is for damages sustained by him because of the injuries suffered by his wife, 'Emma Harrison.
The several cases were tried jointly, with verdict and judgment in each case against the plaintiffs in error, who unsuccessfully made a joint motion for a new trial in the circuit court, and now prosecute their appeal in. the nature of a writ of error. The appeal in error was transferred to this court by the Court of Appeals, because of the constitutional question presented. Acts 1925', chapter 100, section 10.
We are without jurisdiction to consider the several assignments of error directed to the action of the circuit court in overruling the motion for a new trial, for the reason that the plaintiffs in error failed to make their bill of exceptions a part of the record as.required by statute. The bill of exceptions appearing in the transcript cannot be treated as a part of the record, for two reasons :
First. Trial and verdict were had at the January term of the circuit court. On May 1,1928, during the January term, an order was entered reciting that motion for a new trial had been made and that “said motion for a new trial is continued from the January term of Court to the May term, of Court.” The motion was overruled on May 7, 1928, which was the first day of the May term. Acts 1915, chapter 140. The court could then allow only thirty days from the day the motion for a new trial was overruled, within which to file a bill of exceptions. Acts 1919, chapter 157; Acts 1921, chapter 72; National Refining Company v. Littlefield, 142 Tenn., 689; Sells v. State, 156 Tenn., 610; Austin v. State, 157 Tenn., 202. The circuit court allowed plaintiffs in error sixty days within *298which to tile their bill of exceptions, which was contrary to the provisions of the statutes cited. The hill of exceptions was filed on July 11, 1928, which was more than thirty days from the date the motion for a new trial was overruled.
Second. The order overruling the motion for a new trial and granting time for the filing of a bill of exceptions was entered on the minutes of the trial court on May 28,1928; but it recites that the motion was heard on May 7, 1928, and overruled. The concluding sentence of the order is: ‘ ‘ This order is entered nunc pro tunc. ’ ’ The purport and effect of the entry is that the several orders therein were made by the court on May 7, 1928, and should be given effect from that date. The time allowed for filing bill of exceptions, therefore, began to run from the date the order was in fact made, May 7, 1928. The bill of exceptions was filed on July 11th, more than sixty days after the order was made. So, even if the order granting sixty days were authorized by law, it was not complied with, and the bill of exceptions did not become a part of the record.
In this state of the record we may consider only the assignment of error directed to the action of the circuit court in overruling the 'demurrer of the plaintiff in error, Maryland Casualty Company.
The Maryland Casualty Company was sued as the insurer of the Chattanooga Dayton Bus Line and F. S. Wingate, by a policy of insurance procured and issued in accord with the provisions of Private- Acts 1925, chapter 729'. The demurrer challenges the constitutionality of this statute as in violation of article XI, section 8 of the Constitution of the State.
*299This statute was applied and enforced by this court in United States Fidelity and Guaranty Company v. Allen, 158 Tenn., 504; and was construed in State ex rel. v. McLemore, 155 Tenn., 59.
The statute prohibits the operation of motor vehicles for hire, between fixed termini or over a Tegular route, without executing bond or providing insurance, for the benefit of the public and to provide for compensation for injuries to person or property, resulting from the negligent operation of such motor vehicles. Under the provisions of the statute, “any person injured in person or property by the negligent operation of such a motor vehicle is entitled to institute suit jointly against the owner or operator of said machine and the obligor or insurer on said bond or policy.” United States Fidelity & Guaranty Company v. Allen, supra.
The application of the statute is expressly limited to the. operation of motor vehicles in “counties having a population of more than 110’,000 by the Federal Census of 1920, or any subsequent Federal Census.”
It is urged that the effect of this limitation is to confine the application of the statute to the four largest counties of the State, to the prejudice of operators of motor vehicles therein; thereby creating arbitrary dis-criminations, and suspending the general law in the counties within the application of the statute.
The necessity for regulation of traffic on the public highways is directly affected by the density of population. It is a matter of common knowledge that the number of motor vehicles on the highways steadily increases as the traveler approaches the outskirts of the four largest cities of the State, located within the counties to which the statute applies. With the increase of traffic, the danger and likelihood of accidents increase. The *300statute does not alter or affect the measure of the liability of the wrongdoer, hut is designed only to make more certain that the injured may secure compensation. The benefits of the statute do not accrue only to residents of the counties affected, but may be claimed by all persons who visit the centers of population and there suffer wrongful injury within the application of the statute. These and other reasonably' conceivable considerations must be assumed to have impelled the Legislature to consider this regulation necessary, in the centers of population, for the protection of the public, and unnecessary elsewhere in the State. Motlow v. State, 125 Tenn., 547; Memphis v. State ex rel. Ryals, 139 Tenn., 83, 88-89.
The statute is a police regulation, and the decision of the Legislature as to what is a sufficient reason to justify a classification made in such a statute "will not be reviewed by the courts unless it is palpably arbitrary. ’ ’ Darnell v. Shaphard, 156 Tenn., 544, 553.
We are not able to hold that the classification made by the statute is arbitrary. We think it based upon reasonable differences in the effect of the regulated business on the safety of the traveling public, when conducted in the counties of dense population and when conducted in the smaller counties.
The constitutionality of this statute was sustained by a majority-of this’court in the case of J. W. Cole et al. v. Thomas G. Hill, Clerk, MS. opinion filed at Nashville August 1, 1925'; and the conclusion therein reached is here reaffirmed.
The judgment of the circuit court in each of the four cases is accordingly affirmed, with costs. ■