WOLLHEIM, P. J.
Petitioner seeks judicial review of two final orders of the Oregon Department of Transportation (ODOT) that have been consolidated on review. Both orders denied petitioner’s pursuit of a refund for fuel taxes paid pursuant to the International Fuel Tax Agreement (IFTA). The first order, issued on July 3, 2002, concerned fuel taxes paid for the year 1998, and the second order, issued on June 24,2003, concerned fuel taxes paid for the year 1999. Petitioner makes four assignments of error: (1) ODOT erred in concluding that fuel used while a vehicle is idling is taxable under IFTA; (2) ODOT erred in concluding that petitioner must seek a refund for taxes paid from each respective jurisdiction; (3) ODOT erred in concluding that it lawfully adopted and implemented IFTA; and (4) ODOT erred in concluding that IFTA does not violate the Compact Clause, Article I, section 10, clause 3, of the United States Constitution. We reject each of petitioner’s challenges and affirm.
I. FACTS
Petitioner is assessed a fuel tax by ODOT pursuant to IFTA, which is a “multi-jurisdictional agreement that is intended to encourage cooperation in the administration and collection of motor fuel use tax.”
May Trucking Co. v. Oregon Dept. of Transportation,
388 F3d 1261-62 (9th Cir 2004) (internal quotation marks omitted).
Federal law mandates that states that choose to impose a fuel tax must participate in IFTA. 49 USC § 31705 (1994). ODOT has the authority to enter into an international fuel tax agreement under ORS 825.555.
In 1993, ODOT passed a resolution adopting the
1993 version of IFTA, with an effective date of January 1994. In 1996, ODOT renewed Oregon’s membership in IFTA by adopting the 1996 amendments.
Essentially, “IFTA enables carriers to file a consolidated tax return in a carrier’s ‘base jurisdiction;’ the base jurisdiction, upon collection of the tax, distributes the revenue to those other jurisdictions in which the carrier operates.”
Hi-Way Dispatch v. Dept. of State Revenue,
756 NE2d 587, 594 (Ind Tax 2001). Because Oregon is petitioner’s “base jurisdiction,” IFTA allows petitioner to submit one fuel tax return to ODOT instead of having to file a return in every state where petitioner’s trucks have operated. Oregon is in a unique situation because, unlike other jurisdictions, it does not itself assess a fuel tax, but instead relies on a weight/mile tax. Thus, Oregon’s participation in IFTA is solely to ease the administrative burden that filing returns state by state would impose on Oregon-based motor carriers and other members to the agreement.
The current disputes originated in June 2000 from ODOT Case No. 86504. In that case, ODOT issued a Notice of Audited Tax Liability to petitioner for the period from April 1, 1996 through December 31,1998, alleging that petitioner owed $491,891.14 in unpaid fuel taxes, interest, and penalties. Petitioner requested a hearing to contest the audit, and a hearing was held in March 2001. At the hearing, petitioner challenged ODOT’s auditing practices and made arguments regarding whether the authority to enter into IFTA was properly delegated to ODOT, whether ODOT followed proper procedures in adopting IFTA, whether fuel consumed while idling was taxable under IFTA, and whether IFTA violated the Compact Clause of the United States Constitution. At the hearing, both parties presented lengthy testimony regarding petitioner’s record-keeping practices and ODOT’s auditing practices.
In a July 23, 2001, proposed order, the administrative law judge (ALJ) first found that petitioner’s records were inadequate under IFTA. The ALJ concluded, however, that the audit ODOT performed was unreasonable. The ALJ
based that conclusion on ODOT’s exclusion of the highest miles per gallon segments of petitioner’s records from its calculations, and ODOT’s assumption that, every time petitioner’s vehicles were refueled, they were “topped off.” The ALJ ruled that petitioner’s argument regarding idle time was not ripe for adjudication, and rejected petitioner’s arguments regarding IFTA’s validity. Ultimately, the ALJ concluded that neither party established petitioner’s liability and that petitioner would be subject to further audit.
After the proposed order was issued, the parties entered into a written stipulation that provided:
“1. Petitioner and [ODOT] have agreed that [ODOT] will conduct no further IFTA Fuel Tax Audits for the Audit Period. Petitioner has paid the amounts due as reported in its original returns. No amounts for fuel tax, penalties, or interest are due from petitioner for the Audit Period.
“2.
Petitioner agrees not to seek a refund for IFTA Fuel Taxes for the audit period,
except for a refund for fuel consumed while a truck is idling (‘idle time’ issue),
which petitioner intends to pursue for the year 1998. By execution hereof, respondent does not agree that petitioner is entitled to a refund, or that petitioner can pursue its refund claim from respondent ODOT.
“IT IS SO STIPULATED AND AGREED.”
(Internal citations omitted; emphasis added.) The stipulation was signed by attorneys for both parties. No final order was ever issued by ODOT in Case No. 86504.
Based on that stipulation, petitioner requested another hearing to contest the “idle time” issue, which became ODOT Case No. 99044. In its brief to the ALJ, petitioner not only raised arguments regarding the “idle time” issue, but also raised the same arguments concerning the delegation of authority, the adoption of IFTA, and whether IFTA violates the Compact Clause. In response, ODOT filed a motion to strike all portions of petitioner’s brief except for petitioner’s argument regarding the “idle time” issue. ODOT argued that, due to the stipulation, petitioner had waived all of its arguments regarding the validity of IFTA, and that the only issue that could properly be argued was the “idle time” issue.
In a March 2002 proposed order, the ALJ concluded that, pursuant to the stipulation, petitioner had waived all of its arguments regarding the validity of IFTA. In addition, the ALJ concluded that IFTA did not preclude taxation for idle time and that the only tax year before him was 1998, not 1999 as petitioner argued. In a July 2002 final order, ODOT adopted the findings and conclusions of the ALJ. In addition, ODOT concluded that, under the language of IFTA, if petitioner wished to pursue a refund for idle time, it had to do so in the individual jurisdiction to which the tax was owed and could not file a refund request in Oregon. Petitioner sought judicial review of that final order.
While that petition was pending, petitioner requested a refund for idle time for the tax year 1999. ODOT denied petitioner’s request, and petitioner requested a hearing, held in December 2002, which became ODOT Case No. 99706. Petitioner raised the same arguments as before regarding idle time and the validity of IFTA. In a proposed order, the ALJ again rejected petitioner’s argument regarding idle time, and, this time, addressed and rejected on the merits petitioner’s claims regarding IFTA’s validity. In a June 2003 final order, ODOT rejected petitioner’s claims and adopted the findings and conclusions of the proposed order. Petitioner sought judicial review. In July 2003, petitioner filed a motion to consolidate the petitions. We granted petitioner’s motion. We address the two final orders issued by ODOT separately, beginning with the June 2003 final order.
II. JUNE 2003 FINAL ORDER
We begin with petitioner’s contentions concerning the validity of IFTA. In its third assignment of error, petitioner argues first that “the Oregon Legislature failed to properly adopt IFTA and delegate its administration to ODOT pursuant to ORS 825.555 which only references a generic international fuel tax agreement, not IFTA.” Second, petitioner argues that, even if the legislature properly delegated to ODOT the authority to enter into IFTA, ODOT failed to properly adopt both the 1993 version of IFTA and the 1996 amendments to IFTA. Third, petitioner argues that IFTA’s adoption was subject to the rulemaking procedures of the
Administrative Procedures Act (APA) and that ODOT failed to follow those procedures.
In response, ODOT asserts, respectively, that ORS 825.555 authorized ODOT to enter into IFTA, that petitioner has failed to present any evidence that ODOT failed to follow proper procedures, and that ODOT, by promulgation of OAR 740-200-040, adopted by rule the 1996 amendments to IFTA. We agree with ODOT.
A.
Delegation
We first examine whether ORS 825.555 authorized ODOT to enter into IFTA. Our review is for errors of law. ORS 825.555 provides, in part:
“(1) The Department of Transportation may enter into an international fuel tax agreement with jurisdictions outside of this state to provide for cooperation and assistance among member jurisdictions in the administration and collection of taxes imposed on motor carriers for the consumption of all fuels used in vehicles operated interstate.
«‡ sji ‡ if: ‡
“(3) An agreement
may not provide
for any benefit, exemption or privilege with respect to any fees or taxes levied or assessed against the use of highways or use or ownership of vehicles except for motor fuel taxes and requirements related to motor fuel taxes.”
(Emphasis added.)
Petitioner asserts that ORS 825.555 is an invalid delegation of power by the legislature because it did not adopt the
specific
international fuel tax agreement that ODOT entered into and because the statute adopts future tax agreements. Before this court, petitioner cites no authority in support of its assertion. Petitioner’s brief to ODOT cited
Demers v. Peterson,
197 Or 466, 254 P2d 213 (1953), and
Brinkley v. Motor Vehicles Division,
47 Or App 25, 613 P2d
1071 (1980). We discuss those cases in turn and reject petitioner’s contentions.
Demers
involved the constitutionality of the Oregon Agricultural Chemical Control Act. 197 Or at 468. That act stated that “ £[t]he department may, after public hearing, make regulations for carrying out the provisions of this Act.’ ”
Id.
at 469. The Supreme Court held that the statute
gave
the department “unlimited power to make regulations to carry out the provisions of the act[.] * * * There is no suggestion in the title of the act or in the act itself of the nature, extent or character of the regulations.”
Id.
at 470. The court held the act unconstitutional because “the act contains no rule or standard fixed for the guidance of the administrative [agency] .’’Id.
In contrast to the statute at issue in
Demers,
ORS 825.555(1) specifically provides that ODOT only may enter into an international fuel tax agreement to “provide for cooperation and assistance among member jurisdictions in the administration and collection of [fuel] taxes [.]” In addition, subsection (3) makes it clear that ODOT’s authority extends only to fuel taxes, and cannot include unrelated provisions in the agreement. In order to be a proper delegation of power, the statute must “furnish [ ] adequate
safeguards
to those who are affected[.]”
Warren v. Marion County et al,
222 Or 307, 314, 353 P2d 257 (1960) (emphasis in original). ORS 825.555 provides those safeguards by limiting ODOT’s authority to enter into agreements for cooperation and assistance among jurisdictions in the administration and collection of fuel taxes.
Demers
does not support petitioner’s argument.
Petitioner cited
Brinkley
below in support of its argument that ORS 825.555 improperly adopts future tax agreements. In
Brinkley,
this court declared unconstitutional a local ordinance that “purported to adopt all state statutory amendments to the definitions of traffic offenses ‘which * * * hereafter may be enacted.’ ” 47 Or App at 27. ORS 825.555 does not suffer from the same defect; it does not purport to adopt anything. It simply gives ODOT the authority to enter into an international ffiel tax agreement. Accordingly,
Brinkley
does not support petitioner’s argument.
B.
Procedure
We next address petitioner’s argument that ODOT did not follow proper procedures in entering into and adopting IFTA as provided in ORS 825.555. As previously noted, ODOT first became a member of IFTA in 1993, when it passed a resolution adopting IFTA. Petitioner’s argument essentially boils down to its contention that there is an
absence
of any record of what, if any, procedure ODOT followed in adopting IFTA.
However, petitioner overlooks that it has “the burden of presenting evidence to support [its] position in a contested case * * ORS 183.450(2).
It was petitioner’s obligation to make sure that there is evidence in the record supporting its position.
See, e.g., Lis v. Bd. of Higher Ed.,
34 Or App 215, 218-19, 577 P2d 1370 (1978) (rejecting “no evidence in the record” argument with respect to the plaintiffs claim that the agency did not follow proper procedure). Petitioner did not meet that obligation.
For that
reason, we reject petitioner’s argument that ODOT did not properly adopt and become a member of IFTA.
C.
Rulemaking
We next address petitioner’s argument that IFTA’s provisions are rules that should have been promulgated in accordance with the APA. ODOT responds that IFTA’s provisions are not rules, but are simply part of the agreement entered into, and that, even if IFTA is subject to the requirements of the APA, ODOT promulgated OAR 740-200-040, which adopted IFTA.
In its final order, ODOT rejected petitioner’s challenge based on the adoption of OAR 740-200-040. That rule provides, in part:
“(1) The provisions contained in the International Fuel Tax Agreement (IFTA) Articles of Agreement, the IFTA Audit Manual and the IFTA Procedures Manual, and all amendments thereto in effect April 1,2002, are hereby adopted and prescribed by the Oregon Department of Transportation (ODOT) and apply to Oregon-based motor carriers who participate in IFTA.”
(Boldface in original.) Petitioner does not dispute that, by the adoption of OAR 740-200-040, ODOT promulgated IFTA’s provisions in accordance with the APA. That rule went into effect on November 18, 2002,
before
the hearing date in this case.
Therefore, the question becomes whether ODOT intended OAR 740-200-040 to be applied retroactively; that is, does the rule, adopted in 2002, apply to fuels consumed in 1999?
An agency is allowed to apply a rule retroactively if that is the agency’s intent.
U.S. Bancorp v. Dept. of Rev.,
337
Or 625, 637, 103 P3d 85 (2004). In order to ascertain ODOT’s intent in promulgating OAR 740-200-040, we first examine the text and context of that rule.
Id.
The rule itself is silent as to whether ODOT intended it to apply retroactively. However, an examination of the circumstances surrounding the promulgation of OAR 740-200-040 shows that it was intended to be applied retroactively.
Id.
Our analysis is informed by
Delehant v. Board on Police Standards,
317 Or 273, 855 P2d 1088 (1993). In that case, the petitioner appealed the Board on Police Standards and Training’s (BPST) denial of a police certificate due to his criminal history. The petitioner had been convicted of several misdemeanors in Idaho. Those convictions were eventually set aside and dismissed, and the records of those convictions were expunged by an Idaho court.
Id.
at 275-76. However, based on those convictions, BPST denied the petitioner’s application for certification. After a contested case hearing, BPST again denied the petitioner’s certification. In the Amended Final Order, BPST cited ORS 181.662(l)(b), which grants BPST authority to deny certification if “ ‘the officer * * * has been convicted of a crime in this state or any other jurisdiction.’ ”
Id.
at 276. BPST made no reference to its own rule,
former
OAR 259-10-0559(a)(l) (1989), which was in effect at the start of the petitioner’s hearing and provided that BPST may only deny certification “ Tased upon a finding that the officer * * * had been convicted of a crime designated in any statute of this state as a felony or a crime for which a maximum term of imprisonment of more than one year may be imposed.’ ”
Id.
During the pendency of the petitioner’s contested case, BPST adopted
former
OAR 259-08-070 (2001), which mirrored the language of ORS 181.662(l)(b), giving BPST the authority to deny certification if the petitioner “ “has been convicted of a crime in this state or any other jurisdiction.’ ”
Id.
at 277. Although no reference to the new rule was made in the Amended Final Order, BPST withdrew that order and issued a Second Amended Final Order that made express reference to that rule.
Id.
The Supreme Court held that
former
OAR 259-08-070 (2001) was intended to be applied retroactively.
Id.
at 278. Although the rule itself was silent on the issue, the court
reasoned that, because BPST had “promulgated the rule during the progress of th[e] case, then applied the rule to th[e] case * * * [it] unquestionably intended the rule to apply retroactively.”
That same reasoning applies in this contested case. In ODOT Case No. 99044, ODOT ruled that petitioner had waived through stipulation any arguments concerning the validity of IFTA. OAR 740-200-040 was then promulgated, and ODOT subsequently applied it to the same challenge to the validity of IFTA in the contested case at hand. As in
Delehant,
ODOT’s passage and application of OAR 740-200-040 dining the pendency of this contested case establishes ODOT’s intent to apply the rule retroactively.
Having determined that ODOT intended the rule to be applied retroactively, we still must determine whether that application “prejudicially affected petitioner’s rights.”
Guerrero v. AFSD,
67 Or App 119, 123, 676 P2d 928 (1984). We conclude that there has been no showing of prejudice. The purpose of IFTA is to ease the administrative burden that fuel taxation laws exert on states and motor carriers. IFTA, Article I, R130-R150. IFTA only benefits petitioner and does not change any of petitioner’s substantive obligations to pay fuel taxes. Petitioner admitted as much in its reply brief:
“As a practical matter, if ODOT refunded to May Trucking Company all fuel taxes paid on the grounds that ODOT did not have the authority to collect the taxes, May Trucking Company would still have to pay the over-the-road fuel taxes to the individual jurisdictions in which it operates.
It would serve no useful purpose
for May Trucking Company to challenge ODOT’s authority to collect all fuel taxes. If this court holds that IFTA was not lawfully adopted or is an illegal compact, then Oregon-based carriers such as May Trucking Company
will still have to pay fuel taxes to the jurisdictions in which they
operate.”
(Emphasis added.) There is no prejudice to petitioner in the retroactive application of OAR 740-200-040. Therefore, regardless of whether ODOT was
required
to adopt the terms
of IFTA by rule, ODOT did so and that rule applies in this case. Accordingly, petitioner’s argument fails.
D.
Compact Clause
In petitioner’s fourth assignment of error, he asserts that IFTA violates the Compact Clause of the United States Constitution because it involves a foreign power, Canada, and because Congress never consented to IFTA. ODOT replies that this issue is controlled by
US Steel Corp. v. Multi-State Tax Comm'n,
434 US 452, 54 L Ed 2d 682, 98 S Ct 799 (1978), and that, in any event, Congress has consented to IFTA. We agree with ODOT.
The Compact Clause provides, “No state shall, without the Consent of Congress, * * * enter into any Agreement or Compact with another State, or with a foreign Power * * US Const, Art I, § 10, cl 3. Congress has consented to IFTA. 49 USC § 31705.
IFTA, therefore, satisfies the Compact Clause. Accordingly, we reject petitioner’s argument.
“(a) REPORTING REQUIRMENTS. — After September 30, 1996, a State may establish, maintain, or enforce a law or regulation that has a fuel use tax reporting requirement (including any tax reporting form) only if the requirement conforms with the International Fuel Tax Agreement.
“(b) PAYMENT. — After September 30,1996, a State may establish, maintain, or enforce a law or regulation that provides for the payment of a fuel use tax only if the law or regulation conforms with the International Fuel Tax Agreement as it applies to collection of a fuel use tax by a single base State and proportional sharing of fuel use taxes charged among the States where a commercial motor vehicle is operated.”
E.
“Idle Time”
We next turn to petitioner’s first assignment of error with respect to the June 2003 final order. Petitioner argues that IFTA does not authorize the taxation of fuel consumed while its vehicles are idling. IFTA, Article VIII, R800 (1996), provides that “[t]he
consumption of motor fuels used in the propulsion of qualified motor vehicles,
except fuel consumed that is exempt from taxation by a jurisdiction, is the taxable event
under
this Agreement.”
(Emphasis added.)
Petitioner contends that, because its trucks are not being “propelled” when they are idling, fuel consumed during idle time is not subject to taxation. Petitioner’s argument is based on the plain, ordinary meaning of “propulsion.” ODOT primarily relies on authority from other states rejecting petitioner’s argument. In addition, ODOT argues that, when read with other provisions of IFTA, petitioner’s reading of R800 is implausible. We review ODOT’s reading of R800 for errors of law. ORS 183.482(8)(a).
As explained before, ODOT has adopted IFTA by administrative rule, including the Audit Manual and the Procedures Manual. OAR 740-200-040. The principles of deference to an agency’s interpretation of its own rules apply in this case. After all, this is not a situation in which ODOT adopted by rule an agreement made by another agency; ODOT is the agency vested with the authority to negotiate the terms of and enter into IFTA.
See, e.g., Oregon Restaurant Services v. Oregon State Lottery,
199 Or App 545, 560, 112 P3d 398 (2005) (contract with administrative agency incorporating that agency’s rule by reference entitled to deference). Thus, as long as ODOT’s interpretation “cannot be shown either to be inconsistent with the wording of the rule itself, or with the rule’s context, or with any other source of law, there is no basis on which this court can assert that the rule has been interpreted ‘erroneously.’ ”
Don’t Waste Oregon
Com. v. Energy Facility Siting,
320 Or 132, 142, 881 P2d 119 (1994). For the reasons that follow, we hold that ODOT’s interpretation of IFTA is consistent with the text and context of the agreement.
ODOT’s interpretation is a plausible reading of the text and context. R800 refers to the
“consumption
of motor fuels.” (Emphasis added.) The term “motor fuel” has a specific definition, and is defined as “all fuels
used for the generation of power for propulsion
of qualified motor vehicles.” IFTA, Article II, R239.
Thus, the language in R800 regarding “propulsion” is simply a restatement of the definition of motor fuels.
In addition, IFTA Article VIII, R820, provides:
“All motor fuel acquired that is normally subject to consumption tax is taxable unless proof to the contrary is provided by the licensee. The licensee
must report all fuel placed in the supply tank
of a qualified motor vehicle as taxable on the IFTA tax return.”
In addition, ODOT’s interpretation is consistent with ORS 825.555. ORS 825.555(1) authorizes ODOT to enter into an agreement for the “administration and collection of taxes imposed on motor carriers
for the consumption of all fuels
used in vehicles operated interstate.” (Emphasis added.) ODOT’s interpretation accomplishes just that.
ODOT’s interpretation is further supported by reasoning in the Indiana Tax Court’s decision in
Hi-Way Dispatch.
In that case, the court rejected a similar challenge to IFTA. The court stated, “The phrase [‘used in the propulsion’] explains the general use for which fuel must be consumed under IFTA, not the fuel’s specific use at any given
time.”
Id.
at 597.
Accordingly, because ODOT’s interpretation of R800 is consistent with the text and context of the provision itself, we defer to that interpretation.
III. JULY 2002 FINAL ORDER
A.
The Scope of the Stipulation
The first issue we must resolve is whether the stipulation entered into by the parties precludes petitioner from challenging the validity of IFTA in this contested case proceeding. Petitioner contends that, because it raised those issues throughout the prior contested case, it had not waived them. Petitioner also argues that it stipulated to the “idling issue” because the ALJ had ruled against it on its challenges to IFTA’s validity in the ALJ’s proposed order from Case No. 86504, so it did not expect the ALJ to rule again on those issues. ODOT contends that, due to the stipulation, the only reviewable issue in this contested case is the idling issue. We agree with ODOT.
We treat the stipulation between the parties as we would any other agreement. In interpreting an agreement, we must first determine whether the language is ambiguous by examining the text and context of the document as a whole.
Yogman v. Parrott,
325 Or 358, 361, 937 P2d 1019 (1997). The issue of ambiguity is a question of law.
Id.
If the language is unambiguous, the analysis ends. Here, we need not go any further than the unambiguous text of the stipulation.
The stipulation states, “Petitioner agrees not to seek a refund for IFTA Fuel Taxes for the audit period,
except for a refund for fuel consumed while a truck is idling (‘idle time’ issue),
which petitioner intends to pursue for the year 1998.” (Emphasis added.) In Case No. 86504, six distinct issues were argued and briefed: (1) whether petitioner accurately reported its fuel use during the audit period; (2) whether the authority delegated to ODOT to enter into IFTA was proper;
(3) whether ODOT was required to pass the substance of IFTA as rules; (4) whether ODOT failed to provide notice and comment; (5) whether IFTA violates the Compact Clause; and (6) whether IFTA entitles petitioner to a refund for idling time.
The stipulation does not say
except for
the delegation issue, the rulemaking issue, or the Compact Clause issue. The stipulation mentions only one distinct issue unrelated to any of the other issues. In fact, petitioner’s attack on the validity of IFTA would require a refund of the
entire
tax, not just taxes paid for “idle time,” for if IFTA were not a legal compact, ODOT would have no authority to collect
any
taxes. That result is inconsistent with the plain text of the agreement. We conclude that petitioner, by stipulation, waived all arguments regarding the validity of IFTA in this contested case. Accordingly, the sole issue here is the “idle time” issue.
B.
“Idle Time” Issue
For the reasons explained in our discussion of the June 2003 Final Order, IFTA does not exempt “idle time” from taxation. Petitioner, therefore, is not entitled to a refund for “idle time.”
IV. CONCLUSION
In sum, as to the June 2003 Final Order, petitioner’s arguments regarding the validity of IFTA fail. ORS 825.555 is not an improper delegation of power by the legislature, petitioner failed to prove that ODOT did not follow the proper procedures in adopting IFTA, ODOT adopted IFTA by rule, and IFTA does not exempt “idle time” from taxation. As to the July 2002 Final Order, petitioner waived its arguments regarding the validity of IFTA through stipulation and, on the “idle time” issue, the same interpretation of the language of IFTA applies. Accordingly, ODOT did not err in rejecting petitioner’s arguments on those issues.
Affirmed.